class Sequel::Dataset
A dataset represents an SQL
query. Datasets can be used to select, insert, update and delete records.
Query
results are always retrieved on demand, so a dataset can be kept around and reused indefinitely (datasets never cache results):
my_posts = DB[:posts].where(author: 'david') # no records are retrieved my_posts.all # records are retrieved my_posts.all # records are retrieved again
Datasets are frozen and use a functional style where modification methods return modified copies of the the dataset. This allows you to reuse datasets:
posts = DB[:posts] davids_posts = posts.where(author: 'david') old_posts = posts.where{stamp < Date.today - 7} davids_old_posts = davids_posts.where{stamp < Date.today - 7}
Datasets are Enumerable objects, so they can be manipulated using many of the Enumerable methods, such as map
and inject
. Note that there are some methods that Dataset
defines that override methods defined in Enumerable and result in different behavior, such as select
and group_by
.
For more information, see the “Dataset Basics” guide.
Constants
- OPTS
- TRUE_FREEZE
Whether
Dataset#freeze
can actually freeze datasets. True only on ruby 2.4+, as it requires clone(freeze: false)
1 - Methods that return modified datasets
↑ topConstants
- COLUMN_CHANGE_OPTS
The dataset options that require the removal of cached columns if changed.
- CONDITIONED_JOIN_TYPES
These symbols have _join methods created (e.g. inner_join) that call
join_table
with the symbol, passing along the arguments and block from the method call.- EMPTY_ARRAY
- EXTENSIONS
Hash
of extension name symbols to callable objects to load the extension into theDataset
object (usually by extending it with a module defined in the extension).- JOIN_METHODS
All methods that return modified datasets with a joined table added.
- NON_SQL_OPTIONS
Which options don't affect the
SQL
generation. Used by simple_select_all? to determine if this is a simple SELECT * FROM table.- QUERY_METHODS
Methods that return modified datasets
- SIMPLE_SELECT_ALL_ALLOWED_FROM
From types allowed to be considered a simple_select_all
- UNCONDITIONED_JOIN_TYPES
These symbols have _join methods created (e.g. natural_join). They accept a table argument and options hash which is passed to
join_table
, and they raise an error if called with a block.
Public Class Methods
Register an extension callback for Dataset
objects. ext should be the extension name symbol, and mod should either be a Module that the dataset is extended with, or a callable object called with the database object. If mod is not provided, a block can be provided and is treated as the mod object.
If mod is a module, this also registers a Database
extension that will extend all of the database's datasets.
# File lib/sequel/dataset/query.rb 55 def self.register_extension(ext, mod=nil, &block) 56 if mod 57 raise(Error, "cannot provide both mod and block to Dataset.register_extension") if block 58 if mod.is_a?(Module) 59 block = proc{|ds| ds.extend(mod)} 60 Sequel::Database.register_extension(ext){|db| db.extend_datasets(mod)} 61 else 62 block = mod 63 end 64 end 65 Sequel.synchronize{EXTENSIONS[ext] = block} 66 end
Public Instance Methods
Save original clone implementation, as some other methods need to call it internally.
Returns a new clone of the dataset with the given options merged. If the options changed include options in COLUMN_CHANGE_OPTS
, the cached columns are deleted. This method should generally not be called directly by user code.
# File lib/sequel/dataset/query.rb 84 def clone(opts = nil || (return self)) 85 # return self used above because clone is called by almost all 86 # other query methods, and it is the fastest approach 87 c = super(:freeze=>false) 88 c.opts.merge!(opts) 89 unless opts.each_key{|o| break if COLUMN_CHANGE_OPTS.include?(o)} 90 c.clear_columns_cache 91 end 92 c.freeze 93 end
Returns a copy of the dataset with the SQL
DISTINCT clause. The DISTINCT clause is used to remove duplicate rows from the output. If arguments are provided, uses a DISTINCT ON clause, in which case it will only be distinct on those columns, instead of all returned columns. If a block is given, it is treated as a virtual row block, similar to where
. Raises an error if arguments are given and DISTINCT ON is not supported.
DB[:items].distinct # SQL: SELECT DISTINCT * FROM items DB[:items].order(:id).distinct(:id) # SQL: SELECT DISTINCT ON (id) * FROM items ORDER BY id DB[:items].order(:id).distinct{func(:id)} # SQL: SELECT DISTINCT ON (func(id)) * FROM items ORDER BY id
There is support for emualting the DISTINCT ON support in MySQL
, but it does not support the ORDER of the dataset, and also doesn't work in many cases if the ONLY_FULL_GROUP_BY sql_mode is used, which is the default on MySQL
5.7.5+.
# File lib/sequel/dataset/query.rb 123 def distinct(*args, &block) 124 virtual_row_columns(args, block) 125 if args.empty? 126 cached_dataset(:_distinct_ds){clone(:distinct => EMPTY_ARRAY)} 127 else 128 raise(InvalidOperation, "DISTINCT ON not supported") unless supports_distinct_on? 129 clone(:distinct => args.freeze) 130 end 131 end
Adds an EXCEPT clause using a second dataset object. An EXCEPT compound dataset returns all rows in the current dataset that are not in the given dataset. Raises an InvalidOperation
if the operation is not supported. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use EXCEPT ALL instead of EXCEPT, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].except(DB[:other_items]) # SELECT * FROM (SELECT * FROM items EXCEPT SELECT * FROM other_items) AS t1 DB[:items].except(DB[:other_items], all: true, from_self: false) # SELECT * FROM items EXCEPT ALL SELECT * FROM other_items DB[:items].except(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items EXCEPT SELECT * FROM other_items) AS i
# File lib/sequel/dataset/query.rb 150 def except(dataset, opts=OPTS) 151 raise(InvalidOperation, "EXCEPT not supported") unless supports_intersect_except? 152 raise(InvalidOperation, "EXCEPT ALL not supported") if opts[:all] && !supports_intersect_except_all? 153 compound_clone(:except, dataset, opts) 154 end
Performs the inverse of Dataset#where
. Note that if you have multiple filter conditions, this is not the same as a negation of all conditions.
DB[:items].exclude(category: 'software') # SELECT * FROM items WHERE (category != 'software') DB[:items].exclude(category: 'software', id: 3) # SELECT * FROM items WHERE ((category != 'software') OR (id != 3))
Also note that SQL
uses 3-valued boolean logic (true
, false
, NULL
), so the inverse of a true condition is a false condition, and will still not match rows that were NULL originally. If you take the earlier example:
DB[:items].exclude(category: 'software') # SELECT * FROM items WHERE (category != 'software')
Note that this does not match rows where category
is NULL
. This is because NULL
is an unknown value, and you do not know whether or not the NULL
category is software
. You can explicitly specify how to handle NULL
values if you want:
DB[:items].exclude(Sequel.~(category: nil) & {category: 'software'}) # SELECT * FROM items WHERE ((category IS NULL) OR (category != 'software'))
# File lib/sequel/dataset/query.rb 180 def exclude(*cond, &block) 181 add_filter(:where, cond, true, &block) 182 end
Inverts the given conditions and adds them to the HAVING clause.
DB[:items].select_group(:name).exclude_having{count(name) < 2} # SELECT name FROM items GROUP BY name HAVING (count(name) >= 2)
See documentation for exclude for how inversion is handled in regards to SQL
3-valued boolean logic.
# File lib/sequel/dataset/query.rb 191 def exclude_having(*cond, &block) 192 add_filter(:having, cond, true, &block) 193 end
Return a clone of the dataset loaded with the given dataset extensions. If no related extension file exists or the extension does not have specific support for Dataset
objects, an Error
will be raised.
# File lib/sequel/dataset/query.rb 199 def extension(*a) 200 c = _clone(:freeze=>false) 201 c.send(:_extension!, a) 202 c.freeze 203 end
Alias for where.
# File lib/sequel/dataset/query.rb 215 def filter(*cond, &block) 216 where(*cond, &block) 217 end
Returns a cloned dataset with a :update lock style.
DB[:table].for_update # SELECT * FROM table FOR UPDATE
# File lib/sequel/dataset/query.rb 222 def for_update 223 cached_dataset(:_for_update_ds){lock_style(:update)} 224 end
Returns a copy of the dataset with the source changed. If no source is given, removes all tables. If multiple sources are given, it is the same as using a CROSS JOIN (cartesian product) between all tables. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].from # SQL: SELECT * DB[:items].from(:blah) # SQL: SELECT * FROM blah DB[:items].from(:blah, :foo) # SQL: SELECT * FROM blah, foo DB[:items].from{fun(arg)} # SQL: SELECT * FROM fun(arg)
# File lib/sequel/dataset/query.rb 235 def from(*source, &block) 236 virtual_row_columns(source, block) 237 table_alias_num = 0 238 ctes = nil 239 source.map! do |s| 240 case s 241 when Dataset 242 if hoist_cte?(s) 243 ctes ||= [] 244 ctes += s.opts[:with] 245 s = s.clone(:with=>nil) 246 end 247 SQL::AliasedExpression.new(s, dataset_alias(table_alias_num+=1)) 248 when Symbol 249 sch, table, aliaz = split_symbol(s) 250 if aliaz 251 s = sch ? SQL::QualifiedIdentifier.new(sch, table) : SQL::Identifier.new(table) 252 SQL::AliasedExpression.new(s, aliaz.to_sym) 253 else 254 s 255 end 256 else 257 s 258 end 259 end 260 o = {:from=>source.empty? ? nil : source.freeze} 261 o[:with] = ((opts[:with] || EMPTY_ARRAY) + ctes).freeze if ctes 262 o[:num_dataset_sources] = table_alias_num if table_alias_num > 0 263 clone(o) 264 end
Returns a dataset selecting from the current dataset. Options:
- :alias
-
Controls the alias of the table
- :column_aliases
-
Also aliases columns, using derived column lists. Only used in conjunction with :alias.
ds = DB[:items].order(:name).select(:id, :name) # SELECT id,name FROM items ORDER BY name ds.from_self # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS t1 ds.from_self(alias: :foo) # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS foo ds.from_self(alias: :foo, column_aliases: [:c1, :c2]) # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS foo(c1, c2)
# File lib/sequel/dataset/query.rb 283 def from_self(opts=OPTS) 284 fs = {} 285 @opts.keys.each{|k| fs[k] = nil unless non_sql_option?(k)} 286 pr = proc do 287 c = clone(fs).from(opts[:alias] ? as(opts[:alias], opts[:column_aliases]) : self) 288 if cols = _columns 289 c.send(:columns=, cols) 290 end 291 c 292 end 293 294 opts.empty? ? cached_dataset(:_from_self_ds, &pr) : pr.call 295 end
Match any of the columns to any of the patterns. The terms can be strings (which use LIKE) or regular expressions if the database supports that. Note that the total number of pattern matches will be Array(columns).length * Array(terms).length, which could cause performance issues.
Options (all are boolean):
- :all_columns
-
All columns must be matched to any of the given patterns.
- :all_patterns
-
All patterns must match at least one of the columns.
- :case_insensitive
-
Use a case insensitive pattern match (the default is case sensitive if the database supports it).
If both :all_columns and :all_patterns are true, all columns must match all patterns.
Examples:
dataset.grep(:a, '%test%') # SELECT * FROM items WHERE (a LIKE '%test%' ESCAPE '\') dataset.grep([:a, :b], %w'%test% foo') # SELECT * FROM items WHERE ((a LIKE '%test%' ESCAPE '\') OR (a LIKE 'foo' ESCAPE '\') # OR (b LIKE '%test%' ESCAPE '\') OR (b LIKE 'foo' ESCAPE '\')) dataset.grep([:a, :b], %w'%foo% %bar%', all_patterns: true) # SELECT * FROM a WHERE (((a LIKE '%foo%' ESCAPE '\') OR (b LIKE '%foo%' ESCAPE '\')) # AND ((a LIKE '%bar%' ESCAPE '\') OR (b LIKE '%bar%' ESCAPE '\'))) dataset.grep([:a, :b], %w'%foo% %bar%', all_columns: true) # SELECT * FROM a WHERE (((a LIKE '%foo%' ESCAPE '\') OR (a LIKE '%bar%' ESCAPE '\')) # AND ((b LIKE '%foo%' ESCAPE '\') OR (b LIKE '%bar%' ESCAPE '\'))) dataset.grep([:a, :b], %w'%foo% %bar%', all_patterns: true, all_columns: true) # SELECT * FROM a WHERE ((a LIKE '%foo%' ESCAPE '\') AND (b LIKE '%foo%' ESCAPE '\') # AND (a LIKE '%bar%' ESCAPE '\') AND (b LIKE '%bar%' ESCAPE '\'))
# File lib/sequel/dataset/query.rb 332 def grep(columns, patterns, opts=OPTS) 333 column_op = opts[:all_columns] ? :AND : :OR 334 if opts[:all_patterns] 335 conds = Array(patterns).map do |pat| 336 SQL::BooleanExpression.new(column_op, *Array(columns).map{|c| SQL::StringExpression.like(c, pat, opts)}) 337 end 338 where(SQL::BooleanExpression.new(:AND, *conds)) 339 else 340 conds = Array(columns).map do |c| 341 SQL::BooleanExpression.new(:OR, *Array(patterns).map{|pat| SQL::StringExpression.like(c, pat, opts)}) 342 end 343 where(SQL::BooleanExpression.new(column_op, *conds)) 344 end 345 end
Returns a copy of the dataset with the results grouped by the value of the given columns. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].group(:id) # SELECT * FROM items GROUP BY id DB[:items].group(:id, :name) # SELECT * FROM items GROUP BY id, name DB[:items].group{[a, sum(b)]} # SELECT * FROM items GROUP BY a, sum(b)
# File lib/sequel/dataset/query.rb 354 def group(*columns, &block) 355 virtual_row_columns(columns, block) 356 clone(:group => (columns.compact.empty? ? nil : columns.freeze)) 357 end
Returns a dataset grouped by the given column with count by group. Column aliases may be supplied, and will be included in the select clause. If a block is given, it is treated as a virtual row block, similar to where
.
Examples:
DB[:items].group_and_count(:name).all # SELECT name, count(*) AS count FROM items GROUP BY name # => [{:name=>'a', :count=>1}, ...] DB[:items].group_and_count(:first_name, :last_name).all # SELECT first_name, last_name, count(*) AS count FROM items GROUP BY first_name, last_name # => [{:first_name=>'a', :last_name=>'b', :count=>1}, ...] DB[:items].group_and_count(Sequel[:first_name].as(:name)).all # SELECT first_name AS name, count(*) AS count FROM items GROUP BY first_name # => [{:name=>'a', :count=>1}, ...] DB[:items].group_and_count{substr(:first_name, 1, 1).as(:initial)}.all # SELECT substr(first_name, 1, 1) AS initial, count(*) AS count FROM items GROUP BY substr(first_name, 1, 1) # => [{:initial=>'a', :count=>1}, ...]
# File lib/sequel/dataset/query.rb 385 def group_and_count(*columns, &block) 386 select_group(*columns, &block).select_append(COUNT_OF_ALL_AS_COUNT) 387 end
Returns a copy of the dataset with the given columns added to the list of existing columns to group on. If no existing columns are present this method simply sets the columns as the initial ones to group on.
DB[:items].group_append(:b) # SELECT * FROM items GROUP BY b DB[:items].group(:a).group_append(:b) # SELECT * FROM items GROUP BY a, b
# File lib/sequel/dataset/query.rb 395 def group_append(*columns, &block) 396 columns = @opts[:group] + columns if @opts[:group] 397 group(*columns, &block) 398 end
Alias of group
# File lib/sequel/dataset/query.rb 360 def group_by(*columns, &block) 361 group(*columns, &block) 362 end
Adds the appropriate CUBE syntax to GROUP BY.
# File lib/sequel/dataset/query.rb 401 def group_cube 402 raise Error, "GROUP BY CUBE not supported on #{db.database_type}" unless supports_group_cube? 403 clone(:group_options=>:cube) 404 end
Adds the appropriate ROLLUP syntax to GROUP BY.
# File lib/sequel/dataset/query.rb 407 def group_rollup 408 raise Error, "GROUP BY ROLLUP not supported on #{db.database_type}" unless supports_group_rollup? 409 clone(:group_options=>:rollup) 410 end
Adds the appropriate GROUPING SETS syntax to GROUP BY.
# File lib/sequel/dataset/query.rb 413 def grouping_sets 414 raise Error, "GROUP BY GROUPING SETS not supported on #{db.database_type}" unless supports_grouping_sets? 415 clone(:group_options=>:"grouping sets") 416 end
Returns a copy of the dataset with the HAVING conditions changed. See where
for argument types.
DB[:items].group(:sum).having(sum: 10) # SELECT * FROM items GROUP BY sum HAVING (sum = 10)
# File lib/sequel/dataset/query.rb 422 def having(*cond, &block) 423 add_filter(:having, cond, &block) 424 end
Adds an INTERSECT clause using a second dataset object. An INTERSECT compound dataset returns all rows in both the current dataset and the given dataset. Raises an InvalidOperation
if the operation is not supported. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use INTERSECT ALL instead of INTERSECT, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].intersect(DB[:other_items]) # SELECT * FROM (SELECT * FROM items INTERSECT SELECT * FROM other_items) AS t1 DB[:items].intersect(DB[:other_items], all: true, from_self: false) # SELECT * FROM items INTERSECT ALL SELECT * FROM other_items DB[:items].intersect(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items INTERSECT SELECT * FROM other_items) AS i
# File lib/sequel/dataset/query.rb 443 def intersect(dataset, opts=OPTS) 444 raise(InvalidOperation, "INTERSECT not supported") unless supports_intersect_except? 445 raise(InvalidOperation, "INTERSECT ALL not supported") if opts[:all] && !supports_intersect_except_all? 446 compound_clone(:intersect, dataset, opts) 447 end
Inverts the current WHERE and HAVING clauses. If there is neither a WHERE or HAVING clause, adds a WHERE clause that is always false.
DB[:items].where(category: 'software').invert # SELECT * FROM items WHERE (category != 'software') DB[:items].where(category: 'software', id: 3).invert # SELECT * FROM items WHERE ((category != 'software') OR (id != 3))
See documentation for exclude for how inversion is handled in regards to SQL
3-valued boolean logic.
# File lib/sequel/dataset/query.rb 460 def invert 461 cached_dataset(:_invert_ds) do 462 having, where = @opts.values_at(:having, :where) 463 if having.nil? && where.nil? 464 where(false) 465 else 466 o = {} 467 o[:having] = SQL::BooleanExpression.invert(having) if having 468 o[:where] = SQL::BooleanExpression.invert(where) if where 469 clone(o) 470 end 471 end 472 end
Alias of inner_join
# File lib/sequel/dataset/query.rb 475 def join(*args, &block) 476 inner_join(*args, &block) 477 end
Returns a joined dataset. Not usually called directly, users should use the appropriate join method (e.g. join, left_join, natural_join, cross_join) which fills in the type
argument.
Takes the following arguments:
- type
-
The type of join to do (e.g. :inner)
- table
-
table to join into the current dataset. Generally one of the following types:
String
,Symbol
-
identifier used as table or view name
Dataset
-
a subselect is performed with an alias of tN for some value of N
SQL::Function
-
set returning function
SQL::AliasedExpression
-
already aliased expression. Uses given alias unless overridden by the :table_alias option.
- expr
-
conditions used when joining, depends on type:
Hash
,Array
of pairs-
Assumes key (1st arg) is column of joined table (unless already qualified), and value (2nd arg) is column of the last joined or primary table (or the :implicit_qualifier option). To specify multiple conditions on a single joined table column, you must use an array. Uses a JOIN with an ON clause.
Array
-
If all members of the array are symbols, considers them as columns and uses a JOIN with a USING clause. Most databases will remove duplicate columns from the result set if this is used.
- nil
-
If a block is not given, doesn't use ON or USING, so the JOIN should be a NATURAL or CROSS join. If a block is given, uses an ON clause based on the block, see below.
- otherwise
-
Treats the argument as a filter expression, so strings are considered literal, symbols specify boolean columns, and
Sequel
expressions can be used. Uses a JOIN with an ON clause.
- options
-
a hash of options, with the following keys supported:
- :table_alias
-
Override the table alias used when joining. In general you shouldn't use this option, you should provide the appropriate
SQL::AliasedExpression
as the table argument. - :implicit_qualifier
-
The name to use for qualifying implicit conditions. By default, the last joined or primary table is used.
- :reset_implicit_qualifier
-
Can set to false to ignore this join when future joins determine qualifier for implicit conditions.
- :qualify
-
Can be set to false to not do any implicit qualification. Can be set to :deep to use the
Qualifier
AST Transformer, which will attempt to qualify subexpressions of the expression tree. Can be set to :symbol to only qualify symbols. Defaults to the value of default_join_table_qualification.
- block
-
The block argument should only be given if a JOIN with an ON clause is used, in which case it yields the table alias/name for the table currently being joined, the table alias/name for the last joined (or first table), and an array of previous
SQL::JoinClause
. Unlikewhere
, this block is not treated as a virtual row block.
Examples:
DB[:a].join_table(:cross, :b) # SELECT * FROM a CROSS JOIN b DB[:a].join_table(:inner, DB[:b], c: d) # SELECT * FROM a INNER JOIN (SELECT * FROM b) AS t1 ON (t1.c = a.d) DB[:a].join_table(:left, Sequel[:b].as(:c), [:d]) # SELECT * FROM a LEFT JOIN b AS c USING (d) DB[:a].natural_join(:b).join_table(:inner, :c) do |ta, jta, js| (Sequel.qualify(ta, :d) > Sequel.qualify(jta, :e)) & {Sequel.qualify(ta, :f)=>DB.from(js.first.table).select(:g)} end # SELECT * FROM a NATURAL JOIN b INNER JOIN c # ON ((c.d > b.e) AND (c.f IN (SELECT g FROM b)))
# File lib/sequel/dataset/query.rb 538 def join_table(type, table, expr=nil, options=OPTS, &block) 539 if hoist_cte?(table) 540 s, ds = hoist_cte(table) 541 return s.join_table(type, ds, expr, options, &block) 542 end 543 544 using_join = expr.is_a?(Array) && !expr.empty? && expr.all?{|x| x.is_a?(Symbol)} 545 if using_join && !supports_join_using? 546 h = {} 547 expr.each{|e| h[e] = e} 548 return join_table(type, table, h, options) 549 end 550 551 table_alias = options[:table_alias] 552 553 if table.is_a?(SQL::AliasedExpression) 554 table_expr = if table_alias 555 SQL::AliasedExpression.new(table.expression, table_alias, table.columns) 556 else 557 table 558 end 559 table = table_expr.expression 560 table_name = table_alias = table_expr.alias 561 elsif table.is_a?(Dataset) 562 if table_alias.nil? 563 table_alias_num = (@opts[:num_dataset_sources] || 0) + 1 564 table_alias = dataset_alias(table_alias_num) 565 end 566 table_name = table_alias 567 table_expr = SQL::AliasedExpression.new(table, table_alias) 568 else 569 table, implicit_table_alias = split_alias(table) 570 table_alias ||= implicit_table_alias 571 table_name = table_alias || table 572 table_expr = table_alias ? SQL::AliasedExpression.new(table, table_alias) : table 573 end 574 575 join = if expr.nil? and !block 576 SQL::JoinClause.new(type, table_expr) 577 elsif using_join 578 raise(Sequel::Error, "can't use a block if providing an array of symbols as expr") if block 579 SQL::JoinUsingClause.new(expr, type, table_expr) 580 else 581 last_alias = options[:implicit_qualifier] || @opts[:last_joined_table] || first_source_alias 582 qualify_type = options[:qualify] 583 if Sequel.condition_specifier?(expr) 584 expr = expr.map do |k, v| 585 qualify_type = default_join_table_qualification if qualify_type.nil? 586 case qualify_type 587 when false 588 nil # Do no qualification 589 when :deep 590 k = Sequel::Qualifier.new(table_name).transform(k) 591 v = Sequel::Qualifier.new(last_alias).transform(v) 592 else 593 k = qualified_column_name(k, table_name) if k.is_a?(Symbol) 594 v = qualified_column_name(v, last_alias) if v.is_a?(Symbol) 595 end 596 [k,v] 597 end 598 expr = SQL::BooleanExpression.from_value_pairs(expr) 599 end 600 if block 601 expr2 = yield(table_name, last_alias, @opts[:join] || EMPTY_ARRAY) 602 expr = expr ? SQL::BooleanExpression.new(:AND, expr, expr2) : expr2 603 end 604 SQL::JoinOnClause.new(expr, type, table_expr) 605 end 606 607 opts = {:join => ((@opts[:join] || EMPTY_ARRAY) + [join]).freeze} 608 opts[:last_joined_table] = table_name unless options[:reset_implicit_qualifier] == false 609 opts[:num_dataset_sources] = table_alias_num if table_alias_num 610 clone(opts) 611 end
Marks this dataset as a lateral dataset. If used in another dataset's FROM or JOIN clauses, it will surround the subquery with LATERAL to enable it to deal with previous tables in the query:
DB.from(:a, DB[:b].where(Sequel[:a][:c]=>Sequel[:b][:d]).lateral) # SELECT * FROM a, LATERAL (SELECT * FROM b WHERE (a.c = b.d))
# File lib/sequel/dataset/query.rb 632 def lateral 633 cached_dataset(:_lateral_ds){clone(:lateral=>true)} 634 end
If given an integer, the dataset will contain only the first l results. If given a range, it will contain only those at offsets within that range. If a second argument is given, it is used as an offset. To use an offset without a limit, pass nil as the first argument.
DB[:items].limit(10) # SELECT * FROM items LIMIT 10 DB[:items].limit(10, 20) # SELECT * FROM items LIMIT 10 OFFSET 20 DB[:items].limit(10...20) # SELECT * FROM items LIMIT 10 OFFSET 10 DB[:items].limit(10..20) # SELECT * FROM items LIMIT 11 OFFSET 10 DB[:items].limit(nil, 20) # SELECT * FROM items OFFSET 20
# File lib/sequel/dataset/query.rb 646 def limit(l, o = (no_offset = true; nil)) 647 return from_self.limit(l, o) if @opts[:sql] 648 649 if l.is_a?(Range) 650 no_offset = false 651 o = l.first 652 l = l.last - l.first + (l.exclude_end? ? 0 : 1) 653 end 654 l = l.to_i if l.is_a?(String) && !l.is_a?(LiteralString) 655 if l.is_a?(Integer) 656 raise(Error, 'Limits must be greater than or equal to 1') unless l >= 1 657 end 658 659 ds = clone(:limit=>l) 660 ds = ds.offset(o) unless no_offset 661 ds 662 end
Returns a cloned dataset with the given lock style. If style is a string, it will be used directly. You should never pass a string to this method that is derived from user input, as that can lead to SQL
injection.
A symbol may be used for database independent locking behavior, but all supported symbols have separate methods (e.g. for_update
).
DB[:items].lock_style('FOR SHARE NOWAIT') # SELECT * FROM items FOR SHARE NOWAIT DB[:items].lock_style('FOR UPDATE OF table1 SKIP LOCKED') # SELECT * FROM items FOR UPDATE OF table1 SKIP LOCKED
# File lib/sequel/dataset/query.rb 676 def lock_style(style) 677 clone(:lock => style) 678 end
Returns a cloned dataset without a row_proc.
ds = DB[:items].with_row_proc(:invert.to_proc) ds.all # => [{2=>:id}] ds.naked.all # => [{:id=>2}]
# File lib/sequel/dataset/query.rb 685 def naked 686 cached_dataset(:_naked_ds){with_row_proc(nil)} 687 end
Returns a copy of the dataset that will raise a DatabaseLockTimeout instead of waiting for rows that are locked by another transaction
DB[:items].for_update.nowait # SELECT * FROM items FOR UPDATE NOWAIT
# File lib/sequel/dataset/query.rb 694 def nowait 695 cached_dataset(:_nowait_ds) do 696 raise(Error, 'This dataset does not support raises errors instead of waiting for locked rows') unless supports_nowait? 697 clone(:nowait=>true) 698 end 699 end
Returns a copy of the dataset with a specified order. Can be safely combined with limit. If you call limit with an offset, it will override override the offset if you've called offset first.
DB[:items].offset(10) # SELECT * FROM items OFFSET 10
# File lib/sequel/dataset/query.rb 706 def offset(o) 707 o = o.to_i if o.is_a?(String) && !o.is_a?(LiteralString) 708 if o.is_a?(Integer) 709 raise(Error, 'Offsets must be greater than or equal to 0') unless o >= 0 710 end 711 clone(:offset => o) 712 end
Adds an alternate filter to an existing WHERE clause using OR. If there is no WHERE clause, then the default is WHERE true, and OR would be redundant, so return the dataset in that case.
DB[:items].where(:a).or(:b) # SELECT * FROM items WHERE a OR b DB[:items].or(:b) # SELECT * FROM items
# File lib/sequel/dataset/query.rb 720 def or(*cond, &block) 721 if @opts[:where].nil? 722 self 723 else 724 add_filter(:where, cond, false, :OR, &block) 725 end 726 end
Returns a copy of the dataset with the order changed. If the dataset has an existing order, it is ignored and overwritten with this order. If a nil is given the returned dataset has no order. This can accept multiple arguments of varying kinds, such as SQL
functions. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].order(:name) # SELECT * FROM items ORDER BY name DB[:items].order(:a, :b) # SELECT * FROM items ORDER BY a, b DB[:items].order(Sequel.lit('a + b')) # SELECT * FROM items ORDER BY a + b DB[:items].order(Sequel[:a] + :b) # SELECT * FROM items ORDER BY (a + b) DB[:items].order(Sequel.desc(:name)) # SELECT * FROM items ORDER BY name DESC DB[:items].order(Sequel.asc(:name, :nulls=>:last)) # SELECT * FROM items ORDER BY name ASC NULLS LAST DB[:items].order{sum(name).desc} # SELECT * FROM items ORDER BY sum(name) DESC DB[:items].order(nil) # SELECT * FROM items
# File lib/sequel/dataset/query.rb 742 def order(*columns, &block) 743 virtual_row_columns(columns, block) 744 clone(:order => (columns.compact.empty?) ? nil : columns.freeze) 745 end
Returns a copy of the dataset with the order columns added to the end of the existing order.
DB[:items].order(:a).order(:b) # SELECT * FROM items ORDER BY b DB[:items].order(:a).order_append(:b) # SELECT * FROM items ORDER BY a, b
# File lib/sequel/dataset/query.rb 752 def order_append(*columns, &block) 753 columns = @opts[:order] + columns if @opts[:order] 754 order(*columns, &block) 755 end
Alias of order
# File lib/sequel/dataset/query.rb 758 def order_by(*columns, &block) 759 order(*columns, &block) 760 end
Alias of order_append.
# File lib/sequel/dataset/query.rb 763 def order_more(*columns, &block) 764 order_append(*columns, &block) 765 end
Returns a copy of the dataset with the order columns added to the beginning of the existing order.
DB[:items].order(:a).order(:b) # SELECT * FROM items ORDER BY b DB[:items].order(:a).order_prepend(:b) # SELECT * FROM items ORDER BY b, a
# File lib/sequel/dataset/query.rb 772 def order_prepend(*columns, &block) 773 ds = order(*columns, &block) 774 @opts[:order] ? ds.order_append(*@opts[:order]) : ds 775 end
Qualify to the given table, or first source if no table is given.
DB[:items].where(id: 1).qualify # SELECT items.* FROM items WHERE (items.id = 1) DB[:items].where(id: 1).qualify(:i) # SELECT i.* FROM items WHERE (i.id = 1)
# File lib/sequel/dataset/query.rb 784 def qualify(table=(cache=true; first_source)) 785 o = @opts 786 return self if o[:sql] 787 788 pr = proc do 789 h = {} 790 (o.keys & QUALIFY_KEYS).each do |k| 791 h[k] = qualified_expression(o[k], table) 792 end 793 h[:select] = [SQL::ColumnAll.new(table)].freeze if !o[:select] || o[:select].empty? 794 clone(h) 795 end 796 797 cache ? cached_dataset(:_qualify_ds, &pr) : pr.call 798 end
Modify the RETURNING clause, only supported on a few databases. If returning is used, instead of insert returning the autogenerated primary key or update/delete returning the number of modified rows, results are returned using fetch_rows
.
DB[:items].returning # RETURNING * DB[:items].returning(nil) # RETURNING NULL DB[:items].returning(:id, :name) # RETURNING id, name DB[:items].returning.insert(:a=>1) do |hash| # hash for each row inserted, with values for all columns end DB[:items].returning.update(:a=>1) do |hash| # hash for each row updated, with values for all columns end DB[:items].returning.delete(:a=>1) do |hash| # hash for each row deleted, with values for all columns end
# File lib/sequel/dataset/query.rb 818 def returning(*values) 819 if values.empty? 820 cached_dataset(:_returning_ds) do 821 raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert) 822 clone(:returning=>EMPTY_ARRAY) 823 end 824 else 825 raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert) 826 clone(:returning=>values.freeze) 827 end 828 end
Returns a copy of the dataset with the order reversed. If no order is given, the existing order is inverted.
DB[:items].reverse(:id) # SELECT * FROM items ORDER BY id DESC DB[:items].reverse{foo(bar)} # SELECT * FROM items ORDER BY foo(bar) DESC DB[:items].order(:id).reverse # SELECT * FROM items ORDER BY id DESC DB[:items].order(:id).reverse(Sequel.desc(:name)) # SELECT * FROM items ORDER BY name ASC
# File lib/sequel/dataset/query.rb 837 def reverse(*order, &block) 838 if order.empty? && !block 839 cached_dataset(:_reverse_ds){order(*invert_order(@opts[:order]))} 840 else 841 virtual_row_columns(order, block) 842 order(*invert_order(order.empty? ? @opts[:order] : order.freeze)) 843 end 844 end
Alias of reverse
# File lib/sequel/dataset/query.rb 847 def reverse_order(*order, &block) 848 reverse(*order, &block) 849 end
Returns a copy of the dataset with the columns selected changed to the given columns. This also takes a virtual row block, similar to where
.
DB[:items].select(:a) # SELECT a FROM items DB[:items].select(:a, :b) # SELECT a, b FROM items DB[:items].select{[a, sum(b)]} # SELECT a, sum(b) FROM items
# File lib/sequel/dataset/query.rb 858 def select(*columns, &block) 859 virtual_row_columns(columns, block) 860 clone(:select => columns.freeze) 861 end
Returns a copy of the dataset selecting the wildcard if no arguments are given. If arguments are given, treat them as tables and select all columns (using the wildcard) from each table.
DB[:items].select(:a).select_all # SELECT * FROM items DB[:items].select_all(:items) # SELECT items.* FROM items DB[:items].select_all(:items, :foo) # SELECT items.*, foo.* FROM items
# File lib/sequel/dataset/query.rb 870 def select_all(*tables) 871 if tables.empty? 872 cached_dataset(:_select_all_ds){clone(:select => nil)} 873 else 874 select(*tables.map{|t| i, a = split_alias(t); a || i}.map!{|t| SQL::ColumnAll.new(t)}.freeze) 875 end 876 end
Returns a copy of the dataset with the given columns added to the existing selected columns. If no columns are currently selected, it will select the columns given in addition to *.
DB[:items].select(:a).select(:b) # SELECT b FROM items DB[:items].select(:a).select_append(:b) # SELECT a, b FROM items DB[:items].select_append(:b) # SELECT *, b FROM items
# File lib/sequel/dataset/query.rb 885 def select_append(*columns, &block) 886 cur_sel = @opts[:select] 887 if !cur_sel || cur_sel.empty? 888 unless supports_select_all_and_column? 889 return select_all(*(Array(@opts[:from]) + Array(@opts[:join]))).select_append(*columns, &block) 890 end 891 cur_sel = [WILDCARD] 892 end 893 select(*(cur_sel + columns), &block) 894 end
Set both the select and group clauses with the given columns
. Column aliases may be supplied, and will be included in the select clause. This also takes a virtual row block similar to where
.
DB[:items].select_group(:a, :b) # SELECT a, b FROM items GROUP BY a, b DB[:items].select_group(Sequel[:c].as(:a)){f(c2)} # SELECT c AS a, f(c2) FROM items GROUP BY c, f(c2)
# File lib/sequel/dataset/query.rb 905 def select_group(*columns, &block) 906 virtual_row_columns(columns, block) 907 select(*columns).group(*columns.map{|c| unaliased_identifier(c)}) 908 end
Alias for select_append.
# File lib/sequel/dataset/query.rb 911 def select_more(*columns, &block) 912 select_append(*columns, &block) 913 end
Set the server for this dataset to use. Used to pick a specific database shard to run a query against, or to override the default (where SELECT uses :read_only database and all other queries use the :default database). This method is always available but is only useful when database sharding is being used.
DB[:items].all # Uses the :read_only or :default server DB[:items].delete # Uses the :default server DB[:items].server(:blah).delete # Uses the :blah server
# File lib/sequel/dataset/query.rb 924 def server(servr) 925 clone(:server=>servr) 926 end
If the database uses sharding and the current dataset has not had a server set, return a cloned dataset that uses the given server. Otherwise, return the receiver directly instead of returning a clone.
# File lib/sequel/dataset/query.rb 931 def server?(server) 932 if db.sharded? && !opts[:server] 933 server(server) 934 else 935 self 936 end 937 end
Specify that the check for limits/offsets when updating/deleting be skipped for the dataset.
# File lib/sequel/dataset/query.rb 940 def skip_limit_check 941 cached_dataset(:_skip_limit_check_ds) do 942 clone(:skip_limit_check=>true) 943 end 944 end
Skip locked rows when returning results from this dataset.
# File lib/sequel/dataset/query.rb 947 def skip_locked 948 cached_dataset(:_skip_locked_ds) do 949 raise(Error, 'This dataset does not support skipping locked rows') unless supports_skip_locked? 950 clone(:skip_locked=>true) 951 end 952 end
Returns a copy of the dataset with no filters (HAVING or WHERE clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).unfiltered # SELECT * FROM items GROUP BY a
# File lib/sequel/dataset/query.rb 958 def unfiltered 959 cached_dataset(:_unfiltered_ds){clone(:where => nil, :having => nil)} 960 end
Returns a copy of the dataset with no grouping (GROUP or HAVING clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).ungrouped # SELECT * FROM items WHERE b
# File lib/sequel/dataset/query.rb 966 def ungrouped 967 cached_dataset(:_ungrouped_ds){clone(:group => nil, :having => nil)} 968 end
Adds a UNION clause using a second dataset object. A UNION compound dataset returns all rows in either the current dataset or the given dataset. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use UNION ALL instead of UNION, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].union(DB[:other_items]) # SELECT * FROM (SELECT * FROM items UNION SELECT * FROM other_items) AS t1 DB[:items].union(DB[:other_items], all: true, from_self: false) # SELECT * FROM items UNION ALL SELECT * FROM other_items DB[:items].union(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items UNION SELECT * FROM other_items) AS i
# File lib/sequel/dataset/query.rb 986 def union(dataset, opts=OPTS) 987 compound_clone(:union, dataset, opts) 988 end
Returns a copy of the dataset with no limit or offset.
DB[:items].limit(10, 20).unlimited # SELECT * FROM items
# File lib/sequel/dataset/query.rb 993 def unlimited 994 cached_dataset(:_unlimited_ds){clone(:limit=>nil, :offset=>nil)} 995 end
Returns a copy of the dataset with no order.
DB[:items].order(:a).unordered # SELECT * FROM items
# File lib/sequel/dataset/query.rb 1000 def unordered 1001 cached_dataset(:_unordered_ds){clone(:order=>nil)} 1002 end
Returns a copy of the dataset with the given WHERE conditions imposed upon it.
Accepts the following argument types:
Hash
,Array
of pairs-
list of equality/inclusion expressions
Symbol
-
taken as a boolean column argument (e.g. WHERE active)
Sequel::SQL::BooleanExpression
,Sequel::LiteralString
-
an existing condition expression, probably created using the
Sequel
expression filter DSL.
where also accepts a block, which should return one of the above argument types, and is treated the same way. This block yields a virtual row object, which is easy to use to create identifiers and functions. For more details on the virtual row support, see the “Virtual Rows” guide
If both a block and regular argument are provided, they get ANDed together.
Examples:
DB[:items].where(id: 3) # SELECT * FROM items WHERE (id = 3) DB[:items].where(Sequel.lit('price < ?', 100)) # SELECT * FROM items WHERE price < 100 DB[:items].where([[:id, [1,2,3]], [:id, 0..10]]) # SELECT * FROM items WHERE ((id IN (1, 2, 3)) AND ((id >= 0) AND (id <= 10))) DB[:items].where(Sequel.lit('price < 100')) # SELECT * FROM items WHERE price < 100 DB[:items].where(:active) # SELECT * FROM items WHERE :active DB[:items].where{price < 100} # SELECT * FROM items WHERE (price < 100)
Multiple where calls can be chained for scoping:
software = dataset.where(category: 'software').where{price < 100} # SELECT * FROM items WHERE ((category = 'software') AND (price < 100))
See the “Dataset Filtering” guide for more examples and details.
# File lib/sequel/dataset/query.rb 1046 def where(*cond, &block) 1047 add_filter(:where, cond, &block) 1048 end
Return a clone of the dataset with an addition named window that can be referenced in window functions. See Sequel::SQL::Window
for a list of options that can be passed in. Example:
DB[:items].window(:w, :partition=>:c1, :order=>:c2) # SELECT * FROM items WINDOW w AS (PARTITION BY c1 ORDER BY c2)
# File lib/sequel/dataset/query.rb 1056 def window(name, opts) 1057 clone(:window=>((@opts[:window]||EMPTY_ARRAY) + [[name, SQL::Window.new(opts)].freeze]).freeze) 1058 end
Add a common table expression (CTE) with the given name and a dataset that defines the CTE. A common table expression acts as an inline view for the query. Options:
- :args
-
Specify the arguments/columns for the CTE, should be an array of symbols.
- :recursive
-
Specify that this is a recursive CTE
PostgreSQL Specific Options:
- :materialized
-
Set to false to force inlining of the CTE, or true to force not inlining the CTE (PostgreSQL 12+).
DB[:items].with(:items, DB[:syx].where(Sequel[:name].like('A%'))) # WITH items AS (SELECT * FROM syx WHERE (name LIKE 'A%' ESCAPE '\')) SELECT * FROM items
# File lib/sequel/dataset/query.rb 1072 def with(name, dataset, opts=OPTS) 1073 raise(Error, 'This dataset does not support common table expressions') unless supports_cte? 1074 if hoist_cte?(dataset) 1075 s, ds = hoist_cte(dataset) 1076 s.with(name, ds, opts) 1077 else 1078 clone(:with=>((@opts[:with]||EMPTY_ARRAY) + [Hash[opts].merge!(:name=>name, :dataset=>dataset)]).freeze) 1079 end 1080 end
Return a clone of the dataset extended with the given modules. Note that like Object#extend, when multiple modules are provided as arguments the cloned dataset is extended with the modules in reverse order. If a block is provided, a DatasetModule
is created using the block and the clone is extended with that module after any modules given as arguments.
# File lib/sequel/dataset/query.rb 1117 def with_extend(*mods, &block) 1118 c = _clone(:freeze=>false) 1119 c.extend(*mods) unless mods.empty? 1120 c.extend(DatasetModule.new(&block)) if block 1121 c.freeze 1122 end
Add a recursive common table expression (CTE) with the given name, a dataset that defines the nonrecursive part of the CTE, and a dataset that defines the recursive part of the CTE. Options:
- :args
-
Specify the arguments/columns for the CTE, should be an array of symbols.
- :union_all
-
Set to false to use UNION instead of UNION ALL combining the nonrecursive and recursive parts.
DB[:t].with_recursive(:t, DB[:i1].select(:id, :parent_id).where(parent_id: nil), DB[:i1].join(:t, id: :parent_id).select(Sequel[:i1][:id], Sequel[:i1][:parent_id]), :args=>[:id, :parent_id]) # WITH RECURSIVE t(id, parent_id) AS ( # SELECT id, parent_id FROM i1 WHERE (parent_id IS NULL) # UNION ALL # SELECT i1.id, i1.parent_id FROM i1 INNER JOIN t ON (t.id = i1.parent_id) # ) SELECT * FROM t
# File lib/sequel/dataset/query.rb 1098 def with_recursive(name, nonrecursive, recursive, opts=OPTS) 1099 raise(Error, 'This dataset does not support common table expressions') unless supports_cte? 1100 if hoist_cte?(nonrecursive) 1101 s, ds = hoist_cte(nonrecursive) 1102 s.with_recursive(name, ds, recursive, opts) 1103 elsif hoist_cte?(recursive) 1104 s, ds = hoist_cte(recursive) 1105 s.with_recursive(name, nonrecursive, ds, opts) 1106 else 1107 clone(:with=>((@opts[:with]||EMPTY_ARRAY) + [Hash[opts].merge!(:recursive=>true, :name=>name, :dataset=>nonrecursive.union(recursive, {:all=>opts[:union_all] != false, :from_self=>false}))]).freeze) 1108 end 1109 end
Returns a cloned dataset with the given row_proc.
ds = DB[:items] ds.all # => [{:id=>2}] ds.with_row_proc(:invert.to_proc).all # => [{2=>:id}]
# File lib/sequel/dataset/query.rb 1139 def with_row_proc(callable) 1140 clone(:row_proc=>callable) 1141 end
Returns a copy of the dataset with the static SQL
used. This is useful if you want to keep the same row_proc/graph, but change the SQL
used to custom SQL
.
DB[:items].with_sql('SELECT * FROM foo') # SELECT * FROM foo
You can use placeholders in your SQL
and provide arguments for those placeholders:
DB[:items].with_sql('SELECT ? FROM foo', 1) # SELECT 1 FROM foo
You can also provide a method name and arguments to call to get the SQL:
DB[:items].with_sql(:insert_sql, :b=>1) # INSERT INTO items (b) VALUES (1)
Note that datasets that specify custom SQL
using this method will generally ignore future dataset methods that modify the SQL
used, as specifying custom SQL
overrides Sequel's SQL
generator. You should probably limit yourself to the following dataset methods when using this method, or use the implicit_subquery extension:
-
each
-
all
-
single_record
(if only one record could be returned) -
single_value
(if only one record could be returned, and a single column is selected) -
map
-
delete (if a DELETE statement)
-
update (if an UPDATE statement, with no arguments)
-
insert (if an INSERT statement, with no arguments)
-
truncate (if a TRUNCATE statement, with no arguments)
# File lib/sequel/dataset/query.rb 1173 def with_sql(sql, *args) 1174 if sql.is_a?(Symbol) 1175 sql = public_send(sql, *args) 1176 else 1177 sql = SQL::PlaceholderLiteralString.new(sql, args) unless args.empty? 1178 end 1179 clone(:sql=>sql) 1180 end
Protected Instance Methods
Add the dataset to the list of compounds
# File lib/sequel/dataset/query.rb 1185 def compound_clone(type, dataset, opts) 1186 if dataset.is_a?(Dataset) && dataset.opts[:with] && !supports_cte_in_compounds? 1187 s, ds = hoist_cte(dataset) 1188 return s.compound_clone(type, ds, opts) 1189 end 1190 ds = compound_from_self.clone(:compounds=>(Array(@opts[:compounds]).map(&:dup) + [[type, dataset.compound_from_self, opts[:all]].freeze]).freeze) 1191 opts[:from_self] == false ? ds : ds.from_self(opts) 1192 end
Return true if the dataset has a non-nil value for any key in opts.
# File lib/sequel/dataset/query.rb 1195 def options_overlap(opts) 1196 !(@opts.map{|k,v| k unless v.nil?}.compact & opts).empty? 1197 end
Whether this dataset is a simple select from an underlying table, such as:
SELECT * FROM table SELECT table.* FROM table
# File lib/sequel/dataset/query.rb 1206 def simple_select_all? 1207 return false unless (f = @opts[:from]) && f.length == 1 1208 o = @opts.reject{|k,v| v.nil? || non_sql_option?(k)} 1209 from = f.first 1210 from = from.expression if from.is_a?(SQL::AliasedExpression) 1211 1212 if SIMPLE_SELECT_ALL_ALLOWED_FROM.any?{|x| from.is_a?(x)} 1213 case o.length 1214 when 1 1215 true 1216 when 2 1217 (s = o[:select]) && s.length == 1 && s.first.is_a?(SQL::ColumnAll) 1218 else 1219 false 1220 end 1221 else 1222 false 1223 end 1224 end
Private Instance Methods
Load the extensions into the receiver, without checking if the receiver is frozen.
# File lib/sequel/dataset/query.rb 1229 def _extension!(exts) 1230 Sequel.extension(*exts) 1231 exts.each do |ext| 1232 if pr = Sequel.synchronize{EXTENSIONS[ext]} 1233 pr.call(self) 1234 else 1235 raise(Error, "Extension #{ext} does not have specific support handling individual datasets (try: Sequel.extension #{ext.inspect})") 1236 end 1237 end 1238 self 1239 end
If invert is true, invert the condition.
# File lib/sequel/dataset/query.rb 1242 def _invert_filter(cond, invert) 1243 if invert 1244 SQL::BooleanExpression.invert(cond) 1245 else 1246 cond 1247 end 1248 end
Add the given filter condition. Arguments:
- clause
-
Symbol
or whichSQL
clause to effect, should be :where or :having - cond
-
The filter condition to add
- invert
-
Whether the condition should be inverted (true or false)
- combine
-
How to combine the condition with an existing condition, should be :AND or :OR
# File lib/sequel/dataset/query.rb 1255 def add_filter(clause, cond, invert=false, combine=:AND, &block) 1256 if cond == EMPTY_ARRAY && !block 1257 raise Error, "must provide an argument to a filtering method if not passing a block" 1258 end 1259 1260 cond = cond.first if cond.size == 1 1261 1262 empty = cond == OPTS || cond == EMPTY_ARRAY 1263 1264 if empty && !block 1265 self 1266 else 1267 if cond == nil 1268 cond = Sequel::NULL 1269 end 1270 if empty && block 1271 cond = nil 1272 end 1273 1274 cond = _invert_filter(filter_expr(cond, &block), invert) 1275 cond = SQL::BooleanExpression.new(combine, @opts[clause], cond) if @opts[clause] 1276 1277 if cond.nil? 1278 cond = Sequel::NULL 1279 end 1280 1281 clone(clause => cond) 1282 end 1283 end
The default :qualify option to use for join tables if one is not specified.
# File lib/sequel/dataset/query.rb 1286 def default_join_table_qualification 1287 :symbol 1288 end
Return self if the dataset already has a server, or a cloned dataset with the default server otherwise.
# File lib/sequel/dataset/query.rb 1361 def default_server 1362 server?(:default) 1363 end
SQL
expression object based on the expr type. See where
.
# File lib/sequel/dataset/query.rb 1291 def filter_expr(expr = nil, &block) 1292 expr = nil if expr == EMPTY_ARRAY 1293 1294 if block 1295 cond = filter_expr(Sequel.virtual_row(&block)) 1296 cond = SQL::BooleanExpression.new(:AND, filter_expr(expr), cond) if expr 1297 return cond 1298 end 1299 1300 case expr 1301 when Hash 1302 SQL::BooleanExpression.from_value_pairs(expr) 1303 when Array 1304 if Sequel.condition_specifier?(expr) 1305 SQL::BooleanExpression.from_value_pairs(expr) 1306 else 1307 raise Error, "Invalid filter expression: #{expr.inspect}" 1308 end 1309 when LiteralString 1310 LiteralString.new("(#{expr})") 1311 when Numeric, SQL::NumericExpression, SQL::StringExpression, Proc, String 1312 raise Error, "Invalid filter expression: #{expr.inspect}" 1313 when TrueClass, FalseClass 1314 if supports_where_true? 1315 SQL::BooleanExpression.new(:NOOP, expr) 1316 elsif expr 1317 SQL::Constants::SQLTRUE 1318 else 1319 SQL::Constants::SQLFALSE 1320 end 1321 when PlaceholderLiteralizer::Argument 1322 expr.transform{|v| filter_expr(v)} 1323 when SQL::PlaceholderLiteralString 1324 expr.with_parens 1325 else 1326 expr 1327 end 1328 end
Return two datasets, the first a clone of the receiver with the WITH clause from the given dataset added to it, and the second a clone of the given dataset with the WITH clause removed.
# File lib/sequel/dataset/query.rb 1333 def hoist_cte(ds) 1334 [clone(:with => ((opts[:with] || EMPTY_ARRAY) + ds.opts[:with]).freeze), ds.clone(:with => nil)] 1335 end
Whether CTEs need to be hoisted from the given ds into the current ds.
# File lib/sequel/dataset/query.rb 1338 def hoist_cte?(ds) 1339 ds.is_a?(Dataset) && ds.opts[:with] && !supports_cte_in_subqueries? 1340 end
Inverts the given order by breaking it into a list of column references and inverting them.
DB[:items].invert_order([Sequel.desc(:id)]]) #=> [Sequel.asc(:id)] DB[:items].invert_order([:category, Sequel.desc(:price)]) #=> [Sequel.desc(:category), Sequel.asc(:price)]
# File lib/sequel/dataset/query.rb 1347 def invert_order(order) 1348 return unless order 1349 order.map do |f| 1350 case f 1351 when SQL::OrderedExpression 1352 f.invert 1353 else 1354 SQL::OrderedExpression.new(f) 1355 end 1356 end 1357 end
Whether the given option key does not affect the generated SQL
.
# File lib/sequel/dataset/query.rb 1366 def non_sql_option?(key) 1367 NON_SQL_OPTIONS.include?(key) 1368 end
Treat the block
as a virtual_row block if not nil
and add the resulting columns to the columns
array (modifies columns
).
# File lib/sequel/dataset/query.rb 1372 def virtual_row_columns(columns, block) 1373 if block 1374 v = Sequel.virtual_row(&block) 1375 if v.is_a?(Array) 1376 columns.concat(v) 1377 else 1378 columns << v 1379 end 1380 end 1381 end
2 - Methods that execute code on the database
↑ topConstants
- ACTION_METHODS
Action methods defined by
Sequel
that execute code on the database.- COLUMNS_CLONE_OPTIONS
The clone options to use when retrieving columns for a dataset.
- COUNT_SELECT
- EMPTY_SELECT
Public Instance Methods
Inserts the given argument into the database. Returns self so it can be used safely when chaining:
DB[:items] << {id: 0, name: 'Zero'} << DB[:old_items].select(:id, name)
# File lib/sequel/dataset/actions.rb 28 def <<(arg) 29 insert(arg) 30 self 31 end
Returns the first record matching the conditions. Examples:
DB[:table][id: 1] # SELECT * FROM table WHERE (id = 1) LIMIT 1 # => {:id=>1}
# File lib/sequel/dataset/actions.rb 37 def [](*conditions) 38 raise(Error, 'You cannot call Dataset#[] with an integer or with no arguments') if (conditions.length == 1 and conditions.first.is_a?(Integer)) or conditions.length == 0 39 first(*conditions) 40 end
Returns an array with all records in the dataset. If a block is given, the array is iterated over after all items have been loaded.
DB[:table].all # SELECT * FROM table # => [{:id=>1, ...}, {:id=>2, ...}, ...] # Iterate over all rows in the table DB[:table].all{|row| p row}
# File lib/sequel/dataset/actions.rb 50 def all(&block) 51 _all(block){|a| each{|r| a << r}} 52 end
Returns a hash with one column used as key and another used as value. If rows have duplicate values for the key column, the latter row(s) will overwrite the value of the previous row(s). If the value_column is not given or nil, uses the entire hash as the value.
DB[:table].as_hash(:id, :name) # SELECT * FROM table # {1=>'Jim', 2=>'Bob', ...} DB[:table].as_hash(:id) # SELECT * FROM table # {1=>{:id=>1, :name=>'Jim'}, 2=>{:id=>2, :name=>'Bob'}, ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].as_hash([:id, :foo], [:name, :bar]) # SELECT * FROM table # {[1, 3]=>['Jim', 'bo'], [2, 4]=>['Bob', 'be'], ...} DB[:table].as_hash([:id, :name]) # SELECT * FROM table # {[1, 'Jim']=>{:id=>1, :name=>'Jim'}, [2, 'Bob']=>{:id=>2, :name=>'Bob'}, ...}
Options:
- :all
-
Use all instead of each to retrieve the objects
- :hash
-
The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.
# File lib/sequel/dataset/actions.rb 774 def as_hash(key_column, value_column = nil, opts = OPTS) 775 h = opts[:hash] || {} 776 meth = opts[:all] ? :all : :each 777 if value_column 778 return naked.as_hash(key_column, value_column, opts) if row_proc 779 if value_column.is_a?(Array) 780 if key_column.is_a?(Array) 781 public_send(meth){|r| h[r.values_at(*key_column)] = r.values_at(*value_column)} 782 else 783 public_send(meth){|r| h[r[key_column]] = r.values_at(*value_column)} 784 end 785 else 786 if key_column.is_a?(Array) 787 public_send(meth){|r| h[r.values_at(*key_column)] = r[value_column]} 788 else 789 public_send(meth){|r| h[r[key_column]] = r[value_column]} 790 end 791 end 792 elsif key_column.is_a?(Array) 793 public_send(meth){|r| h[key_column.map{|k| r[k]}] = r} 794 else 795 public_send(meth){|r| h[r[key_column]] = r} 796 end 797 h 798 end
Returns the average value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].avg(:number) # SELECT avg(number) FROM table LIMIT 1 # => 3 DB[:table].avg{function(column)} # SELECT avg(function(column)) FROM table LIMIT 1 # => 1
# File lib/sequel/dataset/actions.rb 61 def avg(arg=(no_arg = true), &block) 62 arg = Sequel.virtual_row(&block) if no_arg 63 _aggregate(:avg, arg) 64 end
Returns the columns in the result set in order as an array of symbols. If the columns are currently cached, returns the cached value. Otherwise, a SELECT query is performed to retrieve a single row in order to get the columns.
If you are looking for all columns for a single table and maybe some information about each column (e.g. database type), see Database#schema
.
DB[:table].columns # => [:id, :name]
# File lib/sequel/dataset/actions.rb 75 def columns 76 _columns || columns! 77 end
Ignore any cached column information and perform a query to retrieve a row in order to get the columns.
DB[:table].columns! # => [:id, :name]
# File lib/sequel/dataset/actions.rb 84 def columns! 85 ds = clone(COLUMNS_CLONE_OPTIONS) 86 ds.each{break} 87 88 if cols = ds.cache[:_columns] 89 self.columns = cols 90 else 91 [] 92 end 93 end
Returns the number of records in the dataset. If an argument is provided, it is used as the argument to count. If a block is provided, it is treated as a virtual row, and the result is used as the argument to count.
DB[:table].count # SELECT count(*) AS count FROM table LIMIT 1 # => 3 DB[:table].count(:column) # SELECT count(column) AS count FROM table LIMIT 1 # => 2 DB[:table].count{foo(column)} # SELECT count(foo(column)) AS count FROM table LIMIT 1 # => 1
# File lib/sequel/dataset/actions.rb 108 def count(arg=(no_arg=true), &block) 109 if no_arg && !block 110 cached_dataset(:_count_ds) do 111 aggregate_dataset.select(COUNT_SELECT).single_value_ds 112 end.single_value!.to_i 113 else 114 if block 115 if no_arg 116 arg = Sequel.virtual_row(&block) 117 else 118 raise Error, 'cannot provide both argument and block to Dataset#count' 119 end 120 end 121 122 _aggregate(:count, arg) 123 end 124 end
Deletes the records in the dataset, returning the number of records deleted.
DB[:table].delete # DELETE * FROM table # => 3
# File lib/sequel/dataset/actions.rb 130 def delete(&block) 131 sql = delete_sql 132 if uses_returning?(:delete) 133 returning_fetch_rows(sql, &block) 134 else 135 execute_dui(sql) 136 end 137 end
Iterates over the records in the dataset as they are yielded from the database adapter, and returns self.
DB[:table].each{|row| p row} # SELECT * FROM table
Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, you should use all
instead of each
for the outer queries, or use a separate thread or shard inside each
.
# File lib/sequel/dataset/actions.rb 148 def each 149 if rp = row_proc 150 fetch_rows(select_sql){|r| yield rp.call(r)} 151 else 152 fetch_rows(select_sql){|r| yield r} 153 end 154 self 155 end
Returns true if no records exist in the dataset, false otherwise
DB[:table].empty? # SELECT 1 AS one FROM table LIMIT 1 # => false
# File lib/sequel/dataset/actions.rb 163 def empty? 164 cached_dataset(:_empty_ds) do 165 single_value_ds.unordered.select(EMPTY_SELECT) 166 end.single_value!.nil? 167 end
Returns the first matching record if no arguments are given. If a integer argument is given, it is interpreted as a limit, and then returns all matching records up to that limit. If any other type of argument(s) is passed, it is treated as a filter and the first matching record is returned. If a block is given, it is used to filter the dataset before returning anything.
If there are no records in the dataset, returns nil (or an empty array if an integer argument is given).
Examples:
DB[:table].first # SELECT * FROM table LIMIT 1 # => {:id=>7} DB[:table].first(2) # SELECT * FROM table LIMIT 2 # => [{:id=>6}, {:id=>4}] DB[:table].first(id: 2) # SELECT * FROM table WHERE (id = 2) LIMIT 1 # => {:id=>2} DB[:table].first(Sequel.lit("id = 3")) # SELECT * FROM table WHERE (id = 3) LIMIT 1 # => {:id=>3} DB[:table].first(Sequel.lit("id = ?", 4)) # SELECT * FROM table WHERE (id = 4) LIMIT 1 # => {:id=>4} DB[:table].first{id > 2} # SELECT * FROM table WHERE (id > 2) LIMIT 1 # => {:id=>5} DB[:table].first(Sequel.lit("id > ?", 4)){id < 6} # SELECT * FROM table WHERE ((id > 4) AND (id < 6)) LIMIT 1 # => {:id=>5} DB[:table].first(2){id < 2} # SELECT * FROM table WHERE (id < 2) LIMIT 2 # => [{:id=>1}]
# File lib/sequel/dataset/actions.rb 204 def first(*args, &block) 205 case args.length 206 when 0 207 unless block 208 return single_record 209 end 210 when 1 211 arg = args[0] 212 if arg.is_a?(Integer) 213 res = if block 214 if loader = cached_placeholder_literalizer(:_first_integer_cond_loader) do |pl| 215 where(pl.arg).limit(pl.arg) 216 end 217 218 loader.all(filter_expr(&block), arg) 219 else 220 where(&block).limit(arg).all 221 end 222 else 223 if loader = cached_placeholder_literalizer(:_first_integer_loader) do |pl| 224 limit(pl.arg) 225 end 226 227 loader.all(arg) 228 else 229 limit(arg).all 230 end 231 end 232 233 return res 234 end 235 where_args = args 236 args = arg 237 end 238 239 if loader = cached_where_placeholder_literalizer(where_args||args, block, :_first_cond_loader) do |pl| 240 _single_record_ds.where(pl.arg) 241 end 242 243 loader.first(filter_expr(args, &block)) 244 else 245 _single_record_ds.where(args, &block).single_record! 246 end 247 end
Calls first. If first returns nil (signaling that no row matches), raise a Sequel::NoMatchingRow
exception.
# File lib/sequel/dataset/actions.rb 251 def first!(*args, &block) 252 first(*args, &block) || raise(Sequel::NoMatchingRow.new(self)) 253 end
Return the column value for the first matching record in the dataset. Raises an error if both an argument and block is given.
DB[:table].get(:id) # SELECT id FROM table LIMIT 1 # => 3 ds.get{sum(id)} # SELECT sum(id) AS v FROM table LIMIT 1 # => 6
You can pass an array of arguments to return multiple arguments, but you must make sure each element in the array has an alias that Sequel
can determine:
DB[:table].get([:id, :name]) # SELECT id, name FROM table LIMIT 1 # => [3, 'foo'] DB[:table].get{[sum(id).as(sum), name]} # SELECT sum(id) AS sum, name FROM table LIMIT 1 # => [6, 'foo']
# File lib/sequel/dataset/actions.rb 273 def get(column=(no_arg=true; nil), &block) 274 ds = naked 275 if block 276 raise(Error, 'Must call Dataset#get with an argument or a block, not both') unless no_arg 277 ds = ds.select(&block) 278 column = ds.opts[:select] 279 column = nil if column.is_a?(Array) && column.length < 2 280 else 281 case column 282 when Array 283 ds = ds.select(*column) 284 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 285 if loader = cached_placeholder_literalizer(:_get_loader) do |pl| 286 ds.single_value_ds.select(pl.arg) 287 end 288 289 return loader.get(column) 290 end 291 292 ds = ds.select(column) 293 else 294 if loader = cached_placeholder_literalizer(:_get_alias_loader) do |pl| 295 ds.single_value_ds.select(Sequel.as(pl.arg, :v)) 296 end 297 298 return loader.get(column) 299 end 300 301 ds = ds.select(Sequel.as(column, :v)) 302 end 303 end 304 305 if column.is_a?(Array) 306 if r = ds.single_record 307 r.values_at(*hash_key_symbols(column)) 308 end 309 else 310 ds.single_value 311 end 312 end
Inserts multiple records into the associated table. This method can be used to efficiently insert a large number of records into a table in a single query if the database supports it. Inserts are automatically wrapped in a transaction.
This method is called with a columns array and an array of value arrays:
DB[:table].import([:x, :y], [[1, 2], [3, 4]]) # INSERT INTO table (x, y) VALUES (1, 2) # INSERT INTO table (x, y) VALUES (3, 4)
This method also accepts a dataset instead of an array of value arrays:
DB[:table].import([:x, :y], DB[:table2].select(:a, :b)) # INSERT INTO table (x, y) SELECT a, b FROM table2
Options:
- :commit_every
-
Open a new transaction for every given number of records. For example, if you provide a value of 50, will commit after every 50 records.
- :return
-
When this is set to :primary_key, returns an array of autoincremented primary key values for the rows inserted. This does not have an effect if
values
is aDataset
. - :server
-
Set the server/shard to use for the transaction and insert queries.
- :slice
-
Same as :commit_every, :commit_every takes precedence.
# File lib/sequel/dataset/actions.rb 340 def import(columns, values, opts=OPTS) 341 return @db.transaction{insert(columns, values)} if values.is_a?(Dataset) 342 343 return if values.empty? 344 raise(Error, 'Using Sequel::Dataset#import with an empty column array is not allowed') if columns.empty? 345 ds = opts[:server] ? server(opts[:server]) : self 346 347 if slice_size = opts.fetch(:commit_every, opts.fetch(:slice, default_import_slice)) 348 offset = 0 349 rows = [] 350 while offset < values.length 351 rows << ds._import(columns, values[offset, slice_size], opts) 352 offset += slice_size 353 end 354 rows.flatten 355 else 356 ds._import(columns, values, opts) 357 end 358 end
Inserts values into the associated table. The returned value is generally the value of the autoincremented primary key for the inserted row, assuming that a single row is inserted and the table has an autoincrementing primary key.
insert
handles a number of different argument formats:
- no arguments or single empty hash
-
Uses
DEFAULT
VALUES - single hash
-
Most common format, treats keys as columns and values as values
- single array
-
Treats entries as values, with no columns
- two arrays
-
Treats first array as columns, second array as values
- single
Dataset
-
Treats as an insert based on a selection from the dataset given, with no columns
- array and dataset
-
Treats as an insert based on a selection from the dataset given, with the columns given by the array.
Examples:
DB[:items].insert # INSERT INTO items DEFAULT VALUES DB[:items].insert({}) # INSERT INTO items DEFAULT VALUES DB[:items].insert([1,2,3]) # INSERT INTO items VALUES (1, 2, 3) DB[:items].insert([:a, :b], [1,2]) # INSERT INTO items (a, b) VALUES (1, 2) DB[:items].insert(a: 1, b: 2) # INSERT INTO items (a, b) VALUES (1, 2) DB[:items].insert(DB[:old_items]) # INSERT INTO items SELECT * FROM old_items DB[:items].insert([:a, :b], DB[:old_items]) # INSERT INTO items (a, b) SELECT * FROM old_items
# File lib/sequel/dataset/actions.rb 396 def insert(*values, &block) 397 sql = insert_sql(*values) 398 if uses_returning?(:insert) 399 returning_fetch_rows(sql, &block) 400 else 401 execute_insert(sql) 402 end 403 end
Reverses the order and then runs first
with the given arguments and block. Note that this will not necessarily give you the last record in the dataset, unless you have an unambiguous order. If there is not currently an order for this dataset, raises an Error
.
DB[:table].order(:id).last # SELECT * FROM table ORDER BY id DESC LIMIT 1 # => {:id=>10} DB[:table].order(Sequel.desc(:id)).last(2) # SELECT * FROM table ORDER BY id ASC LIMIT 2 # => [{:id=>1}, {:id=>2}]
# File lib/sequel/dataset/actions.rb 415 def last(*args, &block) 416 raise(Error, 'No order specified') unless @opts[:order] 417 reverse.first(*args, &block) 418 end
Maps column values for each record in the dataset (if an argument is given) or performs the stock mapping functionality of Enumerable
otherwise. Raises an Error
if both an argument and block are given.
DB[:table].map(:id) # SELECT * FROM table # => [1, 2, 3, ...] DB[:table].map{|r| r[:id] * 2} # SELECT * FROM table # => [2, 4, 6, ...]
You can also provide an array of column names:
DB[:table].map([:id, :name]) # SELECT * FROM table # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
# File lib/sequel/dataset/actions.rb 434 def map(column=nil, &block) 435 if column 436 raise(Error, 'Must call Dataset#map with either an argument or a block, not both') if block 437 return naked.map(column) if row_proc 438 if column.is_a?(Array) 439 super(){|r| r.values_at(*column)} 440 else 441 super(){|r| r[column]} 442 end 443 else 444 super(&block) 445 end 446 end
Returns the maximum value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].max(:id) # SELECT max(id) FROM table LIMIT 1 # => 10 DB[:table].max{function(column)} # SELECT max(function(column)) FROM table LIMIT 1 # => 7
# File lib/sequel/dataset/actions.rb 455 def max(arg=(no_arg = true), &block) 456 arg = Sequel.virtual_row(&block) if no_arg 457 _aggregate(:max, arg) 458 end
Returns the minimum value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].min(:id) # SELECT min(id) FROM table LIMIT 1 # => 1 DB[:table].min{function(column)} # SELECT min(function(column)) FROM table LIMIT 1 # => 0
# File lib/sequel/dataset/actions.rb 467 def min(arg=(no_arg = true), &block) 468 arg = Sequel.virtual_row(&block) if no_arg 469 _aggregate(:min, arg) 470 end
This is a front end for import that allows you to submit an array of hashes instead of arrays of columns and values:
DB[:table].multi_insert([{x: 1}, {x: 2}]) # INSERT INTO table (x) VALUES (1) # INSERT INTO table (x) VALUES (2)
Be aware that all hashes should have the same keys if you use this calling method, otherwise some columns could be missed or set to null instead of to default values.
This respects the same options as import
.
# File lib/sequel/dataset/actions.rb 484 def multi_insert(hashes, opts=OPTS) 485 return if hashes.empty? 486 columns = hashes.first.keys 487 import(columns, hashes.map{|h| columns.map{|c| h[c]}}, opts) 488 end
Yields each row in the dataset, but internally uses multiple queries as needed to process the entire result set without keeping all rows in the dataset in memory, even if the underlying driver buffers all query results in memory.
Because this uses multiple queries internally, in order to remain consistent, it also uses a transaction internally. Additionally, to work correctly, the dataset must have unambiguous order. Using an ambiguous order can result in an infinite loop, as well as subtler bugs such as yielding duplicate rows or rows being skipped.
Sequel
checks that the datasets using this method have an order, but it cannot ensure that the order is unambiguous.
Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, use a separate thread or shard inside paged_each
.
Options:
- :rows_per_fetch
-
The number of rows to fetch per query. Defaults to 1000.
- :strategy
-
The strategy to use for paging of results. By default this is :offset, for using an approach with a limit and offset for every page. This can be set to :filter, which uses a limit and a filter that excludes rows from previous pages. In order for this strategy to work, you must be selecting the columns you are ordering by, and none of the columns can contain NULLs. Note that some
Sequel
adapters have optimized implementations that will use cursors or streaming regardless of the :strategy option used. - :filter_values
-
If the strategy: :filter option is used, this option should be a proc that accepts the last retrieved row for the previous page and an array of ORDER BY expressions, and returns an array of values relating to those expressions for the last retrieved row. You will need to use this option if your ORDER BY expressions are not simple columns, if they contain qualified identifiers that would be ambiguous unqualified, if they contain any identifiers that are aliased in SELECT, and potentially other cases.
Examples:
DB[:table].order(:id).paged_each{|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table ORDER BY id LIMIT 1000 OFFSET 1000 # ... DB[:table].order(:id).paged_each(:rows_per_fetch=>100){|row| } # SELECT * FROM table ORDER BY id LIMIT 100 # SELECT * FROM table ORDER BY id LIMIT 100 OFFSET 100 # ... DB[:table].order(:id).paged_each(strategy: :filter){|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000 # ... DB[:table].order(:id).paged_each(strategy: :filter, filter_values: lambda{|row, exprs| [row[:id]]}){|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000 # ...
# File lib/sequel/dataset/actions.rb 545 def paged_each(opts=OPTS) 546 unless @opts[:order] 547 raise Sequel::Error, "Dataset#paged_each requires the dataset be ordered" 548 end 549 unless block_given? 550 return enum_for(:paged_each, opts) 551 end 552 553 total_limit = @opts[:limit] 554 offset = @opts[:offset] 555 if server = @opts[:server] 556 opts = Hash[opts] 557 opts[:server] = server 558 end 559 560 rows_per_fetch = opts[:rows_per_fetch] || 1000 561 strategy = if offset || total_limit 562 :offset 563 else 564 opts[:strategy] || :offset 565 end 566 567 db.transaction(opts) do 568 case strategy 569 when :filter 570 filter_values = opts[:filter_values] || proc{|row, exprs| exprs.map{|e| row[hash_key_symbol(e)]}} 571 base_ds = ds = limit(rows_per_fetch) 572 while ds 573 last_row = nil 574 ds.each do |row| 575 last_row = row 576 yield row 577 end 578 ds = (base_ds.where(ignore_values_preceding(last_row, &filter_values)) if last_row) 579 end 580 else 581 offset ||= 0 582 num_rows_yielded = rows_per_fetch 583 total_rows = 0 584 585 while num_rows_yielded == rows_per_fetch && (total_limit.nil? || total_rows < total_limit) 586 if total_limit && total_rows + rows_per_fetch > total_limit 587 rows_per_fetch = total_limit - total_rows 588 end 589 590 num_rows_yielded = 0 591 limit(rows_per_fetch, offset).each do |row| 592 num_rows_yielded += 1 593 total_rows += 1 if total_limit 594 yield row 595 end 596 597 offset += rows_per_fetch 598 end 599 end 600 end 601 602 self 603 end
Returns a hash with key_column values as keys and value_column values as values. Similar to as_hash
, but only selects the columns given. Like as_hash
, it accepts an optional :hash parameter, into which entries will be merged.
DB[:table].select_hash(:id, :name) # SELECT id, name FROM table # => {1=>'a', 2=>'b', ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].select_hash([:id, :foo], [:name, :bar]) # SELECT id, foo, name, bar FROM table # => {[1, 3]=>['a', 'c'], [2, 4]=>['b', 'd'], ...}
When using this method, you must be sure that each expression has an alias that Sequel
can determine.
# File lib/sequel/dataset/actions.rb 623 def select_hash(key_column, value_column, opts = OPTS) 624 _select_hash(:as_hash, key_column, value_column, opts) 625 end
Returns a hash with key_column values as keys and an array of value_column values. Similar to to_hash_groups
, but only selects the columns given. Like to_hash_groups
, it accepts an optional :hash parameter, into which entries will be merged.
DB[:table].select_hash_groups(:name, :id) # SELECT id, name FROM table # => {'a'=>[1, 4, ...], 'b'=>[2, ...], ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].select_hash_groups([:first, :middle], [:last, :id]) # SELECT first, middle, last, id FROM table # => {['a', 'b']=>[['c', 1], ['d', 2], ...], ...}
When using this method, you must be sure that each expression has an alias that Sequel
can determine.
# File lib/sequel/dataset/actions.rb 644 def select_hash_groups(key_column, value_column, opts = OPTS) 645 _select_hash(:to_hash_groups, key_column, value_column, opts) 646 end
Selects the column given (either as an argument or as a block), and returns an array of all values of that column in the dataset. If you give a block argument that returns an array with multiple entries, the contents of the resulting array are undefined. Raises an Error
if called with both an argument and a block.
DB[:table].select_map(:id) # SELECT id FROM table # => [3, 5, 8, 1, ...] DB[:table].select_map{id * 2} # SELECT (id * 2) FROM table # => [6, 10, 16, 2, ...]
You can also provide an array of column names:
DB[:table].select_map([:id, :name]) # SELECT id, name FROM table # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel
can determine.
# File lib/sequel/dataset/actions.rb 667 def select_map(column=nil, &block) 668 _select_map(column, false, &block) 669 end
The same as select_map
, but in addition orders the array by the column.
DB[:table].select_order_map(:id) # SELECT id FROM table ORDER BY id # => [1, 2, 3, 4, ...] DB[:table].select_order_map{id * 2} # SELECT (id * 2) FROM table ORDER BY (id * 2) # => [2, 4, 6, 8, ...]
You can also provide an array of column names:
DB[:table].select_order_map([:id, :name]) # SELECT id, name FROM table ORDER BY id, name # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel
can determine.
# File lib/sequel/dataset/actions.rb 686 def select_order_map(column=nil, &block) 687 _select_map(column, true, &block) 688 end
Limits the dataset to one record, and returns the first record in the dataset, or nil if the dataset has no records. Users should probably use first
instead of this method. Example:
DB[:test].single_record # SELECT * FROM test LIMIT 1 # => {:column_name=>'value'}
# File lib/sequel/dataset/actions.rb 696 def single_record 697 _single_record_ds.single_record! 698 end
Returns the first record in dataset, without limiting the dataset. Returns nil if the dataset has no records. Users should probably use first
instead of this method. This should only be used if you know the dataset is already limited to a single record. This method may be desirable to use for performance reasons, as it does not clone the receiver. Example:
DB[:test].single_record! # SELECT * FROM test # => {:column_name=>'value'}
# File lib/sequel/dataset/actions.rb 708 def single_record! 709 with_sql_first(select_sql) 710 end
Returns the first value of the first record in the dataset. Returns nil if dataset is empty. Users should generally use get
instead of this method. Example:
DB[:test].single_value # SELECT * FROM test LIMIT 1 # => 'value'
# File lib/sequel/dataset/actions.rb 718 def single_value 719 single_value_ds.each do |r| 720 r.each{|_, v| return v} 721 end 722 nil 723 end
Returns the first value of the first record in the dataset, without limiting the dataset. Returns nil if the dataset is empty. Users should generally use get
instead of this method. Should not be used on graphed datasets or datasets that have row_procs that don't return hashes. This method may be desirable to use for performance reasons, as it does not clone the receiver.
DB[:test].single_value! # SELECT * FROM test # => 'value'
# File lib/sequel/dataset/actions.rb 733 def single_value! 734 with_sql_single_value(select_sql) 735 end
Returns the sum for the given column/expression. Uses a virtual row block if no column is given.
DB[:table].sum(:id) # SELECT sum(id) FROM table LIMIT 1 # => 55 DB[:table].sum{function(column)} # SELECT sum(function(column)) FROM table LIMIT 1 # => 10
# File lib/sequel/dataset/actions.rb 744 def sum(arg=(no_arg = true), &block) 745 arg = Sequel.virtual_row(&block) if no_arg 746 _aggregate(:sum, arg) 747 end
Alias of as_hash
for backwards compatibility.
# File lib/sequel/dataset/actions.rb 801 def to_hash(*a) 802 as_hash(*a) 803 end
Returns a hash with one column used as key and the values being an array of column values. If the value_column is not given or nil, uses the entire hash as the value.
DB[:table].to_hash_groups(:name, :id) # SELECT * FROM table # {'Jim'=>[1, 4, 16, ...], 'Bob'=>[2], ...} DB[:table].to_hash_groups(:name) # SELECT * FROM table # {'Jim'=>[{:id=>1, :name=>'Jim'}, {:id=>4, :name=>'Jim'}, ...], 'Bob'=>[{:id=>2, :name=>'Bob'}], ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].to_hash_groups([:first, :middle], [:last, :id]) # SELECT * FROM table # {['Jim', 'Bob']=>[['Smith', 1], ['Jackson', 4], ...], ...} DB[:table].to_hash_groups([:first, :middle]) # SELECT * FROM table # {['Jim', 'Bob']=>[{:id=>1, :first=>'Jim', :middle=>'Bob', :last=>'Smith'}, ...], ...}
Options:
- :all
-
Use all instead of each to retrieve the objects
- :hash
-
The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.
# File lib/sequel/dataset/actions.rb 829 def to_hash_groups(key_column, value_column = nil, opts = OPTS) 830 h = opts[:hash] || {} 831 meth = opts[:all] ? :all : :each 832 if value_column 833 return naked.to_hash_groups(key_column, value_column, opts) if row_proc 834 if value_column.is_a?(Array) 835 if key_column.is_a?(Array) 836 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r.values_at(*value_column)} 837 else 838 public_send(meth){|r| (h[r[key_column]] ||= []) << r.values_at(*value_column)} 839 end 840 else 841 if key_column.is_a?(Array) 842 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r[value_column]} 843 else 844 public_send(meth){|r| (h[r[key_column]] ||= []) << r[value_column]} 845 end 846 end 847 elsif key_column.is_a?(Array) 848 public_send(meth){|r| (h[key_column.map{|k| r[k]}] ||= []) << r} 849 else 850 public_send(meth){|r| (h[r[key_column]] ||= []) << r} 851 end 852 h 853 end
Truncates the dataset. Returns nil.
DB[:table].truncate # TRUNCATE table # => nil
# File lib/sequel/dataset/actions.rb 859 def truncate 860 execute_ddl(truncate_sql) 861 end
Updates values for the dataset. The returned value is the number of rows updated. values
should be a hash where the keys are columns to set and values are the values to which to set the columns.
DB[:table].update(x: nil) # UPDATE table SET x = NULL # => 10 DB[:table].update(x: Sequel[:x]+1, y: 0) # UPDATE table SET x = (x + 1), y = 0 # => 10
# File lib/sequel/dataset/actions.rb 872 def update(values=OPTS, &block) 873 sql = update_sql(values) 874 if uses_returning?(:update) 875 returning_fetch_rows(sql, &block) 876 else 877 execute_dui(sql) 878 end 879 end
Return an array of all rows matching the given filter condition, also yielding each row to the given block. Basically the same as where(cond).all(&block), except it can be optimized to not create an intermediate dataset.
DB[:table].where_all(id: [1,2,3]) # SELECT * FROM table WHERE (id IN (1, 2, 3))
# File lib/sequel/dataset/actions.rb 887 def where_all(cond, &block) 888 if loader = _where_loader([cond], nil) 889 loader.all(filter_expr(cond), &block) 890 else 891 where(cond).all(&block) 892 end 893 end
Iterate over all rows matching the given filter condition, yielding each row to the given block. Basically the same as where(cond).each(&block), except it can be optimized to not create an intermediate dataset.
DB[:table].where_each(id: [1,2,3]){|row| p row} # SELECT * FROM table WHERE (id IN (1, 2, 3))
# File lib/sequel/dataset/actions.rb 901 def where_each(cond, &block) 902 if loader = _where_loader([cond], nil) 903 loader.each(filter_expr(cond), &block) 904 else 905 where(cond).each(&block) 906 end 907 end
Filter the datasets using the given filter condition, then return a single value. This assumes that the dataset has already been setup to limit the selection to a single column. Basically the same as where(cond).single_value, except it can be optimized to not create an intermediate dataset.
DB[:table].select(:name).where_single_value(id: 1) # SELECT name FROM table WHERE (id = 1) LIMIT 1
# File lib/sequel/dataset/actions.rb 916 def where_single_value(cond) 917 if loader = cached_where_placeholder_literalizer([cond], nil, :_where_single_value_loader) do |pl| 918 single_value_ds.where(pl.arg) 919 end 920 921 loader.get(filter_expr(cond)) 922 else 923 where(cond).single_value 924 end 925 end
Run the given SQL
and return an array of all rows. If a block is given, each row is yielded to the block after all rows are loaded. See with_sql_each.
# File lib/sequel/dataset/actions.rb 929 def with_sql_all(sql, &block) 930 _all(block){|a| with_sql_each(sql){|r| a << r}} 931 end
Execute the given SQL
and return the number of rows deleted. This exists solely as an optimization, replacing with_sql
(sql).delete. It's significantly faster as it does not require cloning the current dataset.
# File lib/sequel/dataset/actions.rb 936 def with_sql_delete(sql) 937 execute_dui(sql) 938 end
Run the given SQL
and yield each returned row to the block.
# File lib/sequel/dataset/actions.rb 942 def with_sql_each(sql) 943 if rp = row_proc 944 _with_sql_dataset.fetch_rows(sql){|r| yield rp.call(r)} 945 else 946 _with_sql_dataset.fetch_rows(sql){|r| yield r} 947 end 948 self 949 end
Run the given SQL
and return the first row, or nil if no rows were returned. See with_sql_each.
# File lib/sequel/dataset/actions.rb 953 def with_sql_first(sql) 954 with_sql_each(sql){|r| return r} 955 nil 956 end
Execute the given SQL
and (on most databases) return the primary key of the inserted row.
# File lib/sequel/dataset/actions.rb 969 def with_sql_insert(sql) 970 execute_insert(sql) 971 end
Run the given SQL
and return the first value in the first row, or nil if no rows were returned. For this to make sense, the SQL
given should select only a single value. See with_sql_each.
# File lib/sequel/dataset/actions.rb 961 def with_sql_single_value(sql) 962 if r = with_sql_first(sql) 963 r.each{|_, v| return v} 964 end 965 end
Protected Instance Methods
Internals of import
. If primary key values are requested, use separate insert commands for each row. Otherwise, call multi_insert_sql
and execute each statement it gives separately.
# File lib/sequel/dataset/actions.rb 978 def _import(columns, values, opts) 979 trans_opts = Hash[opts] 980 trans_opts[:server] = @opts[:server] 981 if opts[:return] == :primary_key 982 @db.transaction(trans_opts){values.map{|v| insert(columns, v)}} 983 else 984 stmts = multi_insert_sql(columns, values) 985 @db.transaction(trans_opts){stmts.each{|st| execute_dui(st)}} 986 end 987 end
Return an array of arrays of values given by the symbols in ret_cols.
# File lib/sequel/dataset/actions.rb 990 def _select_map_multiple(ret_cols) 991 map{|r| r.values_at(*ret_cols)} 992 end
Returns an array of the first value in each row.
# File lib/sequel/dataset/actions.rb 995 def _select_map_single 996 k = nil 997 map{|r| r[k||=r.keys.first]} 998 end
A dataset for returning single values from the current dataset.
# File lib/sequel/dataset/actions.rb 1001 def single_value_ds 1002 clone(:limit=>1).ungraphed.naked 1003 end
Private Instance Methods
Cached placeholder literalizer for methods that return values using aggregate functions.
# File lib/sequel/dataset/actions.rb 1017 def _aggregate(function, arg) 1018 if loader = cached_placeholder_literalizer(:"_#{function}_loader") do |pl| 1019 aggregate_dataset.limit(1).select(SQL::Function.new(function, pl.arg).as(function)) 1020 end 1021 loader.get(arg) 1022 else 1023 aggregate_dataset.get(SQL::Function.new(function, arg).as(function)) 1024 end 1025 end
Internals of all and with_sql_all
# File lib/sequel/dataset/actions.rb 1008 def _all(block) 1009 a = [] 1010 yield a 1011 post_load(a) 1012 a.each(&block) if block 1013 a 1014 end
Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Return nil if no hash key can be determined
# File lib/sequel/dataset/actions.rb 1116 def _hash_key_symbol(s, recursing=false) 1117 case s 1118 when Symbol 1119 _, c, a = split_symbol(s) 1120 (a || c).to_sym 1121 when SQL::Identifier, SQL::Wrapper 1122 _hash_key_symbol(s.value, true) 1123 when SQL::QualifiedIdentifier 1124 _hash_key_symbol(s.column, true) 1125 when SQL::AliasedExpression 1126 _hash_key_symbol(s.alias, true) 1127 when String 1128 s.to_sym if recursing 1129 end 1130 end
Internals of select_hash
and select_hash_groups
# File lib/sequel/dataset/actions.rb 1028 def _select_hash(meth, key_column, value_column, opts=OPTS) 1029 select(*(key_column.is_a?(Array) ? key_column : [key_column]) + (value_column.is_a?(Array) ? value_column : [value_column])). 1030 public_send(meth, hash_key_symbols(key_column), hash_key_symbols(value_column), opts) 1031 end
Internals of select_map
and select_order_map
# File lib/sequel/dataset/actions.rb 1034 def _select_map(column, order, &block) 1035 ds = ungraphed.naked 1036 columns = Array(column) 1037 virtual_row_columns(columns, block) 1038 select_cols = order ? columns.map{|c| c.is_a?(SQL::OrderedExpression) ? c.expression : c} : columns 1039 ds = ds.order(*columns.map{|c| unaliased_identifier(c)}) if order 1040 if column.is_a?(Array) || (columns.length > 1) 1041 ds.select(*select_cols)._select_map_multiple(hash_key_symbols(select_cols)) 1042 else 1043 ds.select(auto_alias_expression(select_cols.first))._select_map_single 1044 end 1045 end
A cached dataset for a single record for this dataset.
# File lib/sequel/dataset/actions.rb 1048 def _single_record_ds 1049 cached_dataset(:_single_record_ds){clone(:limit=>1)} 1050 end
Loader used for where_all
and where_each.
# File lib/sequel/dataset/actions.rb 1053 def _where_loader(where_args, where_block) 1054 cached_where_placeholder_literalizer(where_args, where_block, :_where_loader) do |pl| 1055 where(pl.arg) 1056 end 1057 end
Cached dataset to use for with_sql_#{all,each,first,single_value}. This is used so that the columns returned by the given SQL
do not affect the receiver of the with_sql_* method.
# File lib/sequel/dataset/actions.rb 1234 def _with_sql_dataset 1235 if @opts[:_with_sql_ds] 1236 self 1237 else 1238 cached_dataset(:_with_sql_ds) do 1239 clone(:_with_sql_ds=>true) 1240 end 1241 end 1242 end
Automatically alias the given expression if it does not have an identifiable alias.
# File lib/sequel/dataset/actions.rb 1060 def auto_alias_expression(v) 1061 case v 1062 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 1063 v 1064 else 1065 SQL::AliasedExpression.new(v, :v) 1066 end 1067 end
The default number of rows that can be inserted in a single INSERT statement via import. The default is for no limit.
# File lib/sequel/dataset/actions.rb 1071 def default_import_slice 1072 nil 1073 end
Set the server to use to :default unless it is already set in the passed opts
# File lib/sequel/dataset/actions.rb 1076 def default_server_opts(opts) 1077 if @db.sharded? && !opts.has_key?(:server) 1078 opts = Hash[opts] 1079 opts[:server] = @opts[:server] || :default 1080 end 1081 opts 1082 end
Execute the given select SQL
on the database using execute. Use the :read_only server unless a specific server is set.
# File lib/sequel/dataset/actions.rb 1086 def execute(sql, opts=OPTS, &block) 1087 db = @db 1088 if db.sharded? && !opts.has_key?(:server) 1089 opts = Hash[opts] 1090 opts[:server] = @opts[:server] || (@opts[:lock] ? :default : :read_only) 1091 opts 1092 end 1093 db.execute(sql, opts, &block) 1094 end
Execute the given SQL
on the database using execute_ddl.
# File lib/sequel/dataset/actions.rb 1097 def execute_ddl(sql, opts=OPTS, &block) 1098 @db.execute_ddl(sql, default_server_opts(opts), &block) 1099 nil 1100 end
Execute the given SQL
on the database using execute_dui.
# File lib/sequel/dataset/actions.rb 1103 def execute_dui(sql, opts=OPTS, &block) 1104 @db.execute_dui(sql, default_server_opts(opts), &block) 1105 end
Execute the given SQL
on the database using execute_insert.
# File lib/sequel/dataset/actions.rb 1108 def execute_insert(sql, opts=OPTS, &block) 1109 @db.execute_insert(sql, default_server_opts(opts), &block) 1110 end
Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Raise Error
if the hash key symbol cannot be returned.
# File lib/sequel/dataset/actions.rb 1136 def hash_key_symbol(s) 1137 if v = _hash_key_symbol(s) 1138 v 1139 else 1140 raise(Error, "#{s.inspect} is not supported, should be a Symbol, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression") 1141 end 1142 end
If s is an array, return an array with the given hash key symbols. Otherwise, return a hash key symbol for the given expression If a hash key symbol cannot be determined, raise an error.
# File lib/sequel/dataset/actions.rb 1147 def hash_key_symbols(s) 1148 s.is_a?(Array) ? s.map{|c| hash_key_symbol(c)} : hash_key_symbol(s) 1149 end
Returns an expression that will ignore values preceding the given row, using the receiver's current order. This yields the row and the array of order expressions to the block, which should return an array of values to use.
# File lib/sequel/dataset/actions.rb 1154 def ignore_values_preceding(row) 1155 @opts[:order].map{|v| v.is_a?(SQL::OrderedExpression) ? v.expression : v} 1156 1157 order_exprs = @opts[:order].map do |v| 1158 if v.is_a?(SQL::OrderedExpression) 1159 descending = v.descending 1160 v = v.expression 1161 else 1162 descending = false 1163 end 1164 [v, descending] 1165 end 1166 1167 row_values = yield(row, order_exprs.map(&:first)) 1168 1169 last_expr = [] 1170 cond = order_exprs.zip(row_values).map do |(v, descending), value| 1171 expr = last_expr + [SQL::BooleanExpression.new(descending ? :< : :>, v, value)] 1172 last_expr += [SQL::BooleanExpression.new(:'=', v, value)] 1173 Sequel.&(*expr) 1174 end 1175 Sequel.|(*cond) 1176 end
Downcase identifiers by default when outputing them from the database.
# File lib/sequel/dataset/actions.rb 1179 def output_identifier(v) 1180 v = 'untitled' if v == '' 1181 v.to_s.downcase.to_sym 1182 end
This is run inside .all, after all of the records have been loaded via .each, but before any block passed to all is called. It is called with a single argument, an array of all returned records. Does nothing by default, added to make the model eager loading code simpler.
# File lib/sequel/dataset/actions.rb 1188 def post_load(all_records) 1189 end
Called by insert/update/delete when returning is used. Yields each row as a plain hash to the block if one is given, or returns an array of plain hashes for all rows if a block is not given
# File lib/sequel/dataset/actions.rb 1194 def returning_fetch_rows(sql, &block) 1195 if block 1196 default_server.fetch_rows(sql, &block) 1197 nil 1198 else 1199 rows = [] 1200 default_server.fetch_rows(sql){|r| rows << r} 1201 rows 1202 end 1203 end
Return the unaliased part of the identifier. Handles both implicit aliases in symbols, as well as SQL::AliasedExpression
objects. Other objects are returned as is.
# File lib/sequel/dataset/actions.rb 1208 def unaliased_identifier(c) 1209 case c 1210 when Symbol 1211 table, column, aliaz = split_symbol(c) 1212 if aliaz 1213 table ? SQL::QualifiedIdentifier.new(table, column) : Sequel.identifier(column) 1214 else 1215 c 1216 end 1217 when SQL::AliasedExpression 1218 c.expression 1219 when SQL::OrderedExpression 1220 case expr = c.expression 1221 when Symbol, SQL::AliasedExpression 1222 SQL::OrderedExpression.new(unaliased_identifier(expr), c.descending, :nulls=>c.nulls) 1223 else 1224 c 1225 end 1226 else 1227 c 1228 end 1229 end
3 - User Methods relating to SQL Creation
↑ topPublic Instance Methods
Returns an EXISTS
clause for the dataset as an SQL::PlaceholderLiteralString
.
DB.select(1).where(DB[:items].exists) # SELECT 1 WHERE (EXISTS (SELECT * FROM items))
# File lib/sequel/dataset/sql.rb 14 def exists 15 SQL::PlaceholderLiteralString.new(EXISTS, [self], true) 16 end
Returns an INSERT SQL
query string. See insert
.
DB[:items].insert_sql(a: 1) # => "INSERT INTO items (a) VALUES (1)"
# File lib/sequel/dataset/sql.rb 22 def insert_sql(*values) 23 return static_sql(@opts[:sql]) if @opts[:sql] 24 25 check_insert_allowed! 26 27 columns = [] 28 29 case values.size 30 when 0 31 return insert_sql(OPTS) 32 when 1 33 case vals = values[0] 34 when Hash 35 values = [] 36 vals.each do |k,v| 37 columns << k 38 values << v 39 end 40 when Dataset, Array, LiteralString 41 values = vals 42 end 43 when 2 44 if (v0 = values[0]).is_a?(Array) && ((v1 = values[1]).is_a?(Array) || v1.is_a?(Dataset) || v1.is_a?(LiteralString)) 45 columns, values = v0, v1 46 raise(Error, "Different number of values and columns given to insert_sql") if values.is_a?(Array) and columns.length != values.length 47 end 48 end 49 50 if values.is_a?(Array) && values.empty? && !insert_supports_empty_values? 51 columns, values = insert_empty_columns_values 52 elsif values.is_a?(Dataset) && hoist_cte?(values) && supports_cte?(:insert) 53 ds, values = hoist_cte(values) 54 return ds.clone(:columns=>columns, :values=>values).send(:_insert_sql) 55 end 56 clone(:columns=>columns, :values=>values).send(:_insert_sql) 57 end
Append a literal representation of a value to the given SQL
string.
If an unsupported object is given, an Error
is raised.
# File lib/sequel/dataset/sql.rb 62 def literal_append(sql, v) 63 case v 64 when Symbol 65 if skip_symbol_cache? 66 literal_symbol_append(sql, v) 67 else 68 unless l = db.literal_symbol(v) 69 l = String.new 70 literal_symbol_append(l, v) 71 db.literal_symbol_set(v, l) 72 end 73 sql << l 74 end 75 when String 76 case v 77 when LiteralString 78 sql << v 79 when SQL::Blob 80 literal_blob_append(sql, v) 81 else 82 literal_string_append(sql, v) 83 end 84 when Integer 85 sql << literal_integer(v) 86 when Hash 87 literal_hash_append(sql, v) 88 when SQL::Expression 89 literal_expression_append(sql, v) 90 when Float 91 sql << literal_float(v) 92 when BigDecimal 93 sql << literal_big_decimal(v) 94 when NilClass 95 sql << literal_nil 96 when TrueClass 97 sql << literal_true 98 when FalseClass 99 sql << literal_false 100 when Array 101 literal_array_append(sql, v) 102 when Time 103 v.is_a?(SQLTime) ? literal_sqltime_append(sql, v) : literal_time_append(sql, v) 104 when DateTime 105 literal_datetime_append(sql, v) 106 when Date 107 sql << literal_date(v) 108 when Dataset 109 literal_dataset_append(sql, v) 110 else 111 literal_other_append(sql, v) 112 end 113 end
Returns an array of insert statements for inserting multiple records. This method is used by multi_insert
to format insert statements and expects a keys array and and an array of value arrays.
# File lib/sequel/dataset/sql.rb 118 def multi_insert_sql(columns, values) 119 case multi_insert_sql_strategy 120 when :values 121 sql = LiteralString.new('VALUES ') 122 expression_list_append(sql, values.map{|r| Array(r)}) 123 [insert_sql(columns, sql)] 124 when :union 125 c = false 126 sql = LiteralString.new 127 u = ' UNION ALL SELECT ' 128 f = empty_from_sql 129 values.each do |v| 130 if c 131 sql << u 132 else 133 sql << 'SELECT ' 134 c = true 135 end 136 expression_list_append(sql, v) 137 sql << f if f 138 end 139 [insert_sql(columns, sql)] 140 else 141 values.map{|r| insert_sql(columns, r)} 142 end 143 end
Same as select_sql
, not aliased directly to make subclassing simpler.
# File lib/sequel/dataset/sql.rb 146 def sql 147 select_sql 148 end
Returns a TRUNCATE SQL
query string. See truncate
DB[:items].truncate_sql # => 'TRUNCATE items'
# File lib/sequel/dataset/sql.rb 153 def truncate_sql 154 if opts[:sql] 155 static_sql(opts[:sql]) 156 else 157 check_truncation_allowed! 158 check_not_limited!(:truncate) 159 raise(InvalidOperation, "Can't truncate filtered datasets") if opts[:where] || opts[:having] 160 t = String.new 161 source_list_append(t, opts[:from]) 162 _truncate_sql(t) 163 end 164 end
Formats an UPDATE statement using the given values. See update
.
DB[:items].update_sql(price: 100, category: 'software') # => "UPDATE items SET price = 100, category = 'software'
Raises an Error
if the dataset is grouped or includes more than one table.
# File lib/sequel/dataset/sql.rb 173 def update_sql(values = OPTS) 174 return static_sql(opts[:sql]) if opts[:sql] 175 check_update_allowed! 176 check_not_limited!(:update) 177 178 case values 179 when LiteralString 180 # nothing 181 when String 182 raise Error, "plain string passed to Dataset#update is not supported, use Sequel.lit to use a literal string" 183 end 184 185 clone(:values=>values).send(:_update_sql) 186 end
4 - Methods that describe what the dataset supports
↑ topPublic Instance Methods
Whether this dataset will provide accurate number of rows matched for delete and update statements, true by default. Accurate in this case is the number of rows matched by the dataset's filter.
# File lib/sequel/dataset/features.rb 19 def provides_accurate_rows_matched? 20 true 21 end
Whether this dataset quotes identifiers.
# File lib/sequel/dataset/features.rb 12 def quote_identifiers? 13 @opts.fetch(:quote_identifiers, true) 14 end
Whether you must use a column alias list for recursive CTEs, false by default.
# File lib/sequel/dataset/features.rb 24 def recursive_cte_requires_column_aliases? 25 false 26 end
Whether type specifiers are required for prepared statement/bound variable argument placeholders (i.e. :bv__integer), false by default.
# File lib/sequel/dataset/features.rb 36 def requires_placeholder_type_specifiers? 37 false 38 end
Whether the dataset requires SQL
standard datetimes. False by default, as most allow strings with ISO 8601 format.
# File lib/sequel/dataset/features.rb 30 def requires_sql_standard_datetimes? 31 false 32 end
Whether the dataset supports common table expressions, false by default. If given, type
can be :select, :insert, :update, or :delete, in which case it determines whether WITH is supported for the respective statement type.
# File lib/sequel/dataset/features.rb 43 def supports_cte?(type=:select) 44 false 45 end
Whether the dataset supports common table expressions in subqueries, false by default. If false, applies the WITH clause to the main query, which can cause issues if multiple WITH clauses use the same name.
# File lib/sequel/dataset/features.rb 50 def supports_cte_in_subqueries? 51 false 52 end
Whether deleting from joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 55 def supports_deleting_joins? 56 supports_modifying_joins? 57 end
Whether the database supports derived column lists (e.g. “table_expr AS table_alias(column_alias1, column_alias2, …)”), true by default.
# File lib/sequel/dataset/features.rb 62 def supports_derived_column_lists? 63 true 64 end
Whether the dataset supports or can emulate the DISTINCT ON clause, false by default.
# File lib/sequel/dataset/features.rb 67 def supports_distinct_on? 68 false 69 end
Whether the dataset supports CUBE with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 72 def supports_group_cube? 73 false 74 end
Whether the dataset supports ROLLUP with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 77 def supports_group_rollup? 78 false 79 end
Whether the dataset supports GROUPING SETS with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 82 def supports_grouping_sets? 83 false 84 end
Whether this dataset supports the insert_select
method for returning all columns values directly from an insert query, false by default.
# File lib/sequel/dataset/features.rb 88 def supports_insert_select? 89 supports_returning?(:insert) 90 end
Whether the dataset supports the INTERSECT and EXCEPT compound operations, true by default.
# File lib/sequel/dataset/features.rb 93 def supports_intersect_except? 94 true 95 end
Whether the dataset supports the INTERSECT ALL and EXCEPT ALL compound operations, true by default.
# File lib/sequel/dataset/features.rb 98 def supports_intersect_except_all? 99 true 100 end
Whether the dataset supports the IS TRUE syntax, true by default.
# File lib/sequel/dataset/features.rb 103 def supports_is_true? 104 true 105 end
Whether the dataset supports the JOIN table USING (column1, …) syntax, true by default. If false, support is emulated using JOIN table ON (table.column1 = other_table.column1).
# File lib/sequel/dataset/features.rb 109 def supports_join_using? 110 true 111 end
Whether the dataset supports LATERAL for subqueries in the FROM or JOIN clauses, false by default.
# File lib/sequel/dataset/features.rb 114 def supports_lateral_subqueries? 115 false 116 end
Whether modifying joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 129 def supports_modifying_joins? 130 false 131 end
Whether the IN/NOT IN operators support multiple columns when an array of values is given, true by default.
# File lib/sequel/dataset/features.rb 135 def supports_multiple_column_in? 136 true 137 end
Whether the dataset supports skipping raising an error instead of waiting for locked rows when returning data, false by default.
# File lib/sequel/dataset/features.rb 124 def supports_nowait? 125 false 126 end
Whether the dataset supports or can fully emulate the DISTINCT ON clause, including respecting the ORDER BY clause, false by default.
# File lib/sequel/dataset/features.rb 146 def supports_ordered_distinct_on? 147 supports_distinct_on? 148 end
Whether the dataset supports pattern matching by regular expressions, false by default.
# File lib/sequel/dataset/features.rb 151 def supports_regexp? 152 false 153 end
Whether the dataset supports REPLACE syntax, false by default.
# File lib/sequel/dataset/features.rb 156 def supports_replace? 157 false 158 end
Whether the RETURNING clause is supported for the given type of query, false by default. type
can be :insert, :update, or :delete.
# File lib/sequel/dataset/features.rb 162 def supports_returning?(type) 163 false 164 end
Whether the database supports SELECT *, column FROM table
, true by default.
# File lib/sequel/dataset/features.rb 172 def supports_select_all_and_column? 173 true 174 end
Whether the dataset supports skipping locked rows when returning data, false by default.
# File lib/sequel/dataset/features.rb 167 def supports_skip_locked? 168 false 169 end
Whether the dataset supports timezones in literal timestamps, false by default.
# File lib/sequel/dataset/features.rb 177 def supports_timestamp_timezones? 178 false 179 end
Whether the dataset supports fractional seconds in literal timestamps, true by default.
# File lib/sequel/dataset/features.rb 182 def supports_timestamp_usecs? 183 true 184 end
Whether updating joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 187 def supports_updating_joins? 188 supports_modifying_joins? 189 end
Whether the dataset supports WHERE TRUE (or WHERE 1 for databases that that use 1 for true), true by default.
# File lib/sequel/dataset/features.rb 216 def supports_where_true? 217 true 218 end
Whether the dataset supports the WINDOW clause to define windows used by multiple window functions, false by default.
# File lib/sequel/dataset/features.rb 193 def supports_window_clause? 194 false 195 end
Whether the dataset supports the given window function option. True by default. This should only be called if supports_window_functions? is true. Possible options are :rows, :range, :groups, :offset, :exclude.
# File lib/sequel/dataset/features.rb 205 def supports_window_function_frame_option?(option) 206 case option 207 when :rows, :range, :offset 208 true 209 else 210 false 211 end 212 end
Whether the dataset supports window functions, false by default.
# File lib/sequel/dataset/features.rb 198 def supports_window_functions? 199 false 200 end
Private Instance Methods
Whether insert(nil) or insert({}) must be emulated by using at least one value.
# File lib/sequel/dataset/features.rb 224 def insert_supports_empty_values? 225 true 226 end
Whether ORDER BY col NULLS FIRST/LAST must be emulated.
# File lib/sequel/dataset/features.rb 234 def requires_emulating_nulls_first? 235 false 236 end
Whether the dataset needs ESCAPE for LIKE for correct behavior.
# File lib/sequel/dataset/features.rb 229 def requires_like_escape? 230 true 231 end
Whether common table expressions are supported in UNION/INTERSECT/EXCEPT clauses.
# File lib/sequel/dataset/features.rb 239 def supports_cte_in_compounds? 240 supports_cte_in_subqueries? 241 end
Whether the dataset supports the FILTER clause for aggregate functions. If not, support is emulated using CASE.
# File lib/sequel/dataset/features.rb 245 def supports_filtered_aggregates? 246 false 247 end
Whether the database supports quoting function names.
# File lib/sequel/dataset/features.rb 250 def supports_quoted_function_names? 251 false 252 end
Whether the RETURNING clause is used for the given dataset. type
can be :insert, :update, or :delete.
# File lib/sequel/dataset/features.rb 256 def uses_returning?(type) 257 opts[:returning] && !@opts[:sql] && supports_returning?(type) 258 end
Whether the dataset uses WITH ROLLUP/CUBE instead of ROLLUP()/CUBE().
# File lib/sequel/dataset/features.rb 261 def uses_with_rollup? 262 false 263 end
6 - Miscellaneous methods
↑ topAttributes
The database related to this dataset. This is the Database
instance that will execute all of this dataset's queries.
The hash of options for this dataset, keys are symbols.
Public Class Methods
Constructs a new Dataset
instance with an associated database and options. Datasets are usually constructed by invoking the Database#[]
method:
DB[:posts]
Sequel::Dataset
is an abstract class that is not useful by itself. Each database adapter provides a subclass of Sequel::Dataset
, and has the Database#dataset
method return an instance of that subclass.
# File lib/sequel/dataset/misc.rb 25 def initialize(db) 26 @db = db 27 @opts = OPTS 28 @cache = {} 29 freeze 30 end
Public Instance Methods
Define a hash value such that datasets with the same class, DB, and opts will be considered equal.
# File lib/sequel/dataset/misc.rb 34 def ==(o) 35 o.is_a?(self.class) && db == o.db && opts == o.opts 36 end
An object representing the current date or time, should be an instance of Sequel.datetime_class.
# File lib/sequel/dataset/misc.rb 40 def current_datetime 41 Sequel.datetime_class.now 42 end
Return self, as datasets are always frozen.
# File lib/sequel/dataset/misc.rb 50 def dup 51 self 52 end
Yield a dataset for each server in the connection pool that is tied to that server. Intended for use in sharded environments where all servers need to be modified with the same data:
DB[:configs].where(key: 'setting').each_server{|ds| ds.update(value: 'new_value')}
# File lib/sequel/dataset/misc.rb 59 def each_server 60 db.servers.each{|s| yield server(s)} 61 end
Alias for ==
# File lib/sequel/dataset/misc.rb 45 def eql?(o) 46 self == o 47 end
Returns the string with the LIKE metacharacters (% and _) escaped. Useful for when the LIKE term is a user-provided string where metacharacters should not be recognized. Example:
ds.escape_like("foo\\%_") # 'foo\\\%\_'
# File lib/sequel/dataset/misc.rb 68 def escape_like(string) 69 string.gsub(/[\\%_]/){|m| "\\#{m}"} 70 end
Alias of first_source_alias
# File lib/sequel/dataset/misc.rb 91 def first_source 92 first_source_alias 93 end
The first source (primary table) for this dataset. If the dataset doesn't have a table, raises an Error
. If the table is aliased, returns the aliased name.
DB[:table].first_source_alias # => :table DB[Sequel[:table].as(:t)].first_source_alias # => :t
# File lib/sequel/dataset/misc.rb 103 def first_source_alias 104 source = @opts[:from] 105 if source.nil? || source.empty? 106 raise Error, 'No source specified for query' 107 end 108 case s = source.first 109 when SQL::AliasedExpression 110 s.alias 111 when Symbol 112 _, _, aliaz = split_symbol(s) 113 aliaz ? aliaz.to_sym : s 114 else 115 s 116 end 117 end
The first source (primary table) for this dataset. If the dataset doesn't have a table, raises an error. If the table is aliased, returns the original table, not the alias
DB[:table].first_source_table # => :table DB[Sequel[:table].as(:t)].first_source_table # => :table
# File lib/sequel/dataset/misc.rb 128 def first_source_table 129 source = @opts[:from] 130 if source.nil? || source.empty? 131 raise Error, 'No source specified for query' 132 end 133 case s = source.first 134 when SQL::AliasedExpression 135 s.expression 136 when Symbol 137 sch, table, aliaz = split_symbol(s) 138 aliaz ? (sch ? SQL::QualifiedIdentifier.new(sch, table) : table.to_sym) : s 139 else 140 s 141 end 142 end
Freeze the opts when freezing the dataset.
# File lib/sequel/dataset/misc.rb 74 def freeze 75 @opts.freeze 76 super 77 end
Define a hash value such that datasets with the same class, DB, and opts, will have the same hash value.
# File lib/sequel/dataset/misc.rb 146 def hash 147 [self.class, db, opts].hash 148 end
Returns a string representation of the dataset including the class name and the corresponding SQL
select statement.
# File lib/sequel/dataset/misc.rb 152 def inspect 153 "#<#{visible_class_name}: #{sql.inspect}>" 154 end
Whether this dataset is a joined dataset (multiple FROM tables or any JOINs).
# File lib/sequel/dataset/misc.rb 157 def joined_dataset? 158 !!((opts[:from].is_a?(Array) && opts[:from].size > 1) || opts[:join]) 159 end
The alias to use for the row_number column, used when emulating OFFSET support and for eager limit strategies
# File lib/sequel/dataset/misc.rb 163 def row_number_column 164 :x_sequel_row_number_x 165 end
Splits a possible implicit alias in c
, handling both SQL::AliasedExpressions and Symbols. Returns an array of two elements, with the first being the main expression, and the second being the alias.
# File lib/sequel/dataset/misc.rb 176 def split_alias(c) 177 case c 178 when Symbol 179 c_table, column, aliaz = split_symbol(c) 180 [c_table ? SQL::QualifiedIdentifier.new(c_table, column.to_sym) : column.to_sym, aliaz] 181 when SQL::AliasedExpression 182 [c.expression, c.alias] 183 when SQL::JoinClause 184 [c.table, c.table_alias] 185 else 186 [c, nil] 187 end 188 end
This returns an SQL::Identifier
or SQL::AliasedExpression
containing an SQL
identifier that represents the unqualified column for the given value. The given value should be a Symbol
, SQL::Identifier
, SQL::QualifiedIdentifier
, or SQL::AliasedExpression
containing one of those. In other cases, this returns nil.
# File lib/sequel/dataset/misc.rb 195 def unqualified_column_for(v) 196 unless v.is_a?(String) 197 _unqualified_column_for(v) 198 end 199 end
Creates a unique table alias that hasn't already been used in the dataset. table_alias can be any type of object accepted by alias_symbol. The symbol returned will be the implicit alias in the argument, possibly appended with “_N” if the implicit alias has already been used, where N is an integer starting at 0 and increasing until an unused one is found.
You can provide a second addition array argument containing symbols that should not be considered valid table aliases. The current aliases for the FROM and JOIN tables are automatically included in this array.
DB[:table].unused_table_alias(:t) # => :t DB[:table].unused_table_alias(:table) # => :table_0 DB[:table, :table_0].unused_table_alias(:table) # => :table_1 DB[:table, :table_0].unused_table_alias(:table, [:table_1, :table_2]) # => :table_3
# File lib/sequel/dataset/misc.rb 223 def unused_table_alias(table_alias, used_aliases = []) 224 table_alias = alias_symbol(table_alias) 225 used_aliases += opts[:from].map{|t| alias_symbol(t)} if opts[:from] 226 used_aliases += opts[:join].map{|j| j.table_alias ? alias_alias_symbol(j.table_alias) : alias_symbol(j.table)} if opts[:join] 227 if used_aliases.include?(table_alias) 228 i = 0 229 while true 230 ta = :"#{table_alias}_#{i}" 231 return ta unless used_aliases.include?(ta) 232 i += 1 233 end 234 else 235 table_alias 236 end 237 end
Return a modified dataset with quote_identifiers set.
# File lib/sequel/dataset/misc.rb 240 def with_quote_identifiers(v) 241 clone(:quote_identifiers=>v, :skip_symbol_cache=>true) 242 end
Protected Instance Methods
The cached columns for the current dataset.
# File lib/sequel/dataset/misc.rb 271 def _columns 272 cache_get(:_columns) 273 end
Retreive a value from the dataset's cache in a thread safe manner.
# File lib/sequel/dataset/misc.rb 253 def cache_get(k) 254 Sequel.synchronize{@cache[k]} 255 end
Set a value in the dataset's cache in a thread safe manner.
# File lib/sequel/dataset/misc.rb 258 def cache_set(k, v) 259 Sequel.synchronize{@cache[k] = v} 260 end
Clear the columns hash for the current dataset. This is not a thread safe operation, so it should only be used if the dataset could not be used by another thread (such as one that was just created via clone).
# File lib/sequel/dataset/misc.rb 266 def clear_columns_cache 267 @cache.delete(:_columns) 268 end
Private Instance Methods
Internal recursive version of unqualified_column_for
, handling Strings inside of other objects.
# File lib/sequel/dataset/misc.rb 345 def _unqualified_column_for(v) 346 case v 347 when Symbol 348 _, c, a = Sequel.split_symbol(v) 349 c = Sequel.identifier(c) 350 a ? c.as(a) : c 351 when String 352 Sequel.identifier(v) 353 when SQL::Identifier 354 v 355 when SQL::QualifiedIdentifier 356 _unqualified_column_for(v.column) 357 when SQL::AliasedExpression 358 if expr = unqualified_column_for(v.expression) 359 SQL::AliasedExpression.new(expr, v.alias) 360 end 361 end 362 end
Check the cache for the given key, returning the value. Otherwise, yield to get the dataset and cache the dataset under the given key.
# File lib/sequel/dataset/misc.rb 279 def cached_dataset(key) 280 unless ds = cache_get(key) 281 ds = yield 282 cache_set(key, ds) 283 end 284 285 ds 286 end
Return a cached placeholder literalizer for the given key if there is one for this dataset. If there isn't one, increment the counter for the number of calls for the key, and if the counter is at least three, then create a placeholder literalizer by yielding to the block, and cache it.
# File lib/sequel/dataset/misc.rb 293 def cached_placeholder_literalizer(key) 294 if loader = cache_get(key) 295 return loader unless loader.is_a?(Integer) 296 loader += 1 297 298 if loader >= 3 299 loader = Sequel::Dataset::PlaceholderLiteralizer.loader(self){|pl, _| yield pl} 300 cache_set(key, loader) 301 else 302 cache_set(key, loader + 1) 303 loader = nil 304 end 305 elsif cache_sql? 306 cache_set(key, 1) 307 end 308 309 loader 310 end
Return a cached placeholder literalizer for the key, unless where_block is nil and where_args is an empty array or hash. This is designed to guard against placeholder literalizer use when passing arguments to where in the uncached case and filter_expr
if a cached placeholder literalizer is used.
# File lib/sequel/dataset/misc.rb 317 def cached_where_placeholder_literalizer(where_args, where_block, key, &block) 318 where_args = where_args[0] if where_args.length == 1 319 unless where_block 320 return if where_args == OPTS || where_args == EMPTY_ARRAY 321 end 322 323 cached_placeholder_literalizer(key, &block) 324 end
Set the columns for the current dataset.
# File lib/sequel/dataset/misc.rb 327 def columns=(v) 328 cache_set(:_columns, v) 329 end
Set the db, opts, and cache for the copy of the dataset.
# File lib/sequel/dataset/misc.rb 332 def initialize_clone(c, _=nil) 333 @db = c.db 334 @opts = Hash[c.opts] 335 if cols = c.cache_get(:_columns) 336 @cache = {:_columns=>cols} 337 else 338 @cache = {} 339 end 340 end
Return the class name for this dataset, but skip anonymous classes
# File lib/sequel/dataset/misc.rb 365 def visible_class_name 366 c = self.class 367 c = c.superclass while c.name.nil? || c.name == '' 368 c.name 369 end
9 - Internal Methods relating to SQL Creation
↑ topConstants
- BITWISE_METHOD_MAP
- COUNT_FROM_SELF_OPTS
- COUNT_OF_ALL_AS_COUNT
- DEFAULT
- EXISTS
- IS_LITERALS
- IS_OPERATORS
- LIKE_OPERATORS
- N_ARITY_OPERATORS
- QUALIFY_KEYS
- REGEXP_OPERATORS
- TWO_ARITY_OPERATORS
- WILDCARD
Public Class Methods
Given a type (e.g. select) and an array of clauses, return an array of methods to call to build the SQL
string.
# File lib/sequel/dataset/sql.rb 195 def self.clause_methods(type, clauses) 196 clauses.map{|clause| :"#{type}_#{clause}_sql"}.freeze 197 end
Define a dataset literalization method for the given type in the given module, using the given clauses.
Arguments:
- mod
-
Module in which to define method
- type
-
Type of
SQL
literalization method to create, either :select, :insert, :update, or :delete - clauses
-
array of clauses that make up the
SQL
query for the type. This can either be a single array of symbols/strings, or it can be an array of pairs, with the first element in each pair being an if/elsif/else code fragment, and the second element in each pair being an array of symbol/strings for the appropriate branch.
# File lib/sequel/dataset/sql.rb 209 def self.def_sql_method(mod, type, clauses) 210 priv = type == :update || type == :insert 211 cacheable = type == :select || type == :delete 212 213 lines = [] 214 lines << 'private' if priv 215 lines << "def #{'_' if priv}#{type}_sql" 216 lines << 'if sql = opts[:sql]; return static_sql(sql) end' unless priv 217 lines << "if sql = cache_get(:_#{type}_sql); return sql end" if cacheable 218 lines << 'check_delete_allowed!' << 'check_not_limited!(:delete)' if type == :delete 219 lines << 'sql = @opts[:append_sql] || sql_string_origin' 220 221 if clauses.all?{|c| c.is_a?(Array)} 222 clauses.each do |i, cs| 223 lines << i 224 lines.concat(clause_methods(type, cs).map{|x| "#{x}(sql)"}) 225 end 226 lines << 'end' 227 else 228 lines.concat(clause_methods(type, clauses).map{|x| "#{x}(sql)"}) 229 end 230 231 lines << "cache_set(:_#{type}_sql, sql) if cache_sql?" if cacheable 232 lines << 'sql' 233 lines << 'end' 234 235 mod.class_eval lines.join("\n"), __FILE__, __LINE__ 236 end
Public Instance Methods
Append literalization of aliased expression to SQL
string.
# File lib/sequel/dataset/sql.rb 270 def aliased_expression_sql_append(sql, ae) 271 literal_append(sql, ae.expression) 272 as_sql_append(sql, ae.alias, ae.columns) 273 end
Append literalization of array to SQL
string.
# File lib/sequel/dataset/sql.rb 276 def array_sql_append(sql, a) 277 if a.empty? 278 sql << '(NULL)' 279 else 280 sql << '(' 281 expression_list_append(sql, a) 282 sql << ')' 283 end 284 end
Append literalization of boolean constant to SQL
string.
# File lib/sequel/dataset/sql.rb 287 def boolean_constant_sql_append(sql, constant) 288 if (constant == true || constant == false) && !supports_where_true? 289 sql << (constant == true ? '(1 = 1)' : '(1 = 0)') 290 else 291 literal_append(sql, constant) 292 end 293 end
Append literalization of case expression to SQL
string.
# File lib/sequel/dataset/sql.rb 296 def case_expression_sql_append(sql, ce) 297 sql << '(CASE' 298 if ce.expression? 299 sql << ' ' 300 literal_append(sql, ce.expression) 301 end 302 w = " WHEN " 303 t = " THEN " 304 ce.conditions.each do |c,r| 305 sql << w 306 literal_append(sql, c) 307 sql << t 308 literal_append(sql, r) 309 end 310 sql << " ELSE " 311 literal_append(sql, ce.default) 312 sql << " END)" 313 end
Append literalization of cast expression to SQL
string.
# File lib/sequel/dataset/sql.rb 316 def cast_sql_append(sql, expr, type) 317 sql << 'CAST(' 318 literal_append(sql, expr) 319 sql << ' AS ' << db.cast_type_literal(type).to_s 320 sql << ')' 321 end
Append literalization of column all selection to SQL
string.
# File lib/sequel/dataset/sql.rb 324 def column_all_sql_append(sql, ca) 325 qualified_identifier_sql_append(sql, ca.table, WILDCARD) 326 end
Append literalization of complex expression to SQL
string.
# File lib/sequel/dataset/sql.rb 329 def complex_expression_sql_append(sql, op, args) 330 case op 331 when *IS_OPERATORS 332 r = args[1] 333 if r.nil? || supports_is_true? 334 raise(InvalidOperation, 'Invalid argument used for IS operator') unless val = IS_LITERALS[r] 335 sql << '(' 336 literal_append(sql, args[0]) 337 sql << ' ' << op.to_s << ' ' 338 sql << val << ')' 339 elsif op == :IS 340 complex_expression_sql_append(sql, :"=", args) 341 else 342 complex_expression_sql_append(sql, :OR, [SQL::BooleanExpression.new(:"!=", *args), SQL::BooleanExpression.new(:IS, args[0], nil)]) 343 end 344 when :IN, :"NOT IN" 345 cols = args[0] 346 vals = args[1] 347 col_array = true if cols.is_a?(Array) 348 if vals.is_a?(Array) 349 val_array = true 350 empty_val_array = vals == [] 351 end 352 if empty_val_array 353 literal_append(sql, empty_array_value(op, cols)) 354 elsif col_array 355 if !supports_multiple_column_in? 356 if val_array 357 expr = SQL::BooleanExpression.new(:OR, *vals.to_a.map{|vs| SQL::BooleanExpression.from_value_pairs(cols.to_a.zip(vs).map{|c, v| [c, v]})}) 358 literal_append(sql, op == :IN ? expr : ~expr) 359 else 360 old_vals = vals 361 vals = vals.naked if vals.is_a?(Sequel::Dataset) 362 vals = vals.to_a 363 val_cols = old_vals.columns 364 complex_expression_sql_append(sql, op, [cols, vals.map!{|x| x.values_at(*val_cols)}]) 365 end 366 else 367 # If the columns and values are both arrays, use array_sql instead of 368 # literal so that if values is an array of two element arrays, it 369 # will be treated as a value list instead of a condition specifier. 370 sql << '(' 371 literal_append(sql, cols) 372 sql << ' ' << op.to_s << ' ' 373 if val_array 374 array_sql_append(sql, vals) 375 else 376 literal_append(sql, vals) 377 end 378 sql << ')' 379 end 380 else 381 sql << '(' 382 literal_append(sql, cols) 383 sql << ' ' << op.to_s << ' ' 384 literal_append(sql, vals) 385 sql << ')' 386 end 387 when :LIKE, :'NOT LIKE' 388 sql << '(' 389 literal_append(sql, args[0]) 390 sql << ' ' << op.to_s << ' ' 391 literal_append(sql, args[1]) 392 if requires_like_escape? 393 sql << " ESCAPE " 394 literal_append(sql, "\\") 395 end 396 sql << ')' 397 when :ILIKE, :'NOT ILIKE' 398 complex_expression_sql_append(sql, (op == :ILIKE ? :LIKE : :"NOT LIKE"), args.map{|v| Sequel.function(:UPPER, v)}) 399 when :** 400 function_sql_append(sql, Sequel.function(:power, *args)) 401 when *TWO_ARITY_OPERATORS 402 if REGEXP_OPERATORS.include?(op) && !supports_regexp? 403 raise InvalidOperation, "Pattern matching via regular expressions is not supported on #{db.database_type}" 404 end 405 sql << '(' 406 literal_append(sql, args[0]) 407 sql << ' ' << op.to_s << ' ' 408 literal_append(sql, args[1]) 409 sql << ')' 410 when *N_ARITY_OPERATORS 411 sql << '(' 412 c = false 413 op_str = " #{op} " 414 args.each do |a| 415 sql << op_str if c 416 literal_append(sql, a) 417 c ||= true 418 end 419 sql << ')' 420 when :NOT 421 sql << 'NOT ' 422 literal_append(sql, args[0]) 423 when :NOOP 424 literal_append(sql, args[0]) 425 when :'B~' 426 sql << '~' 427 literal_append(sql, args[0]) 428 when :extract 429 sql << 'extract(' << args[0].to_s << ' FROM ' 430 literal_append(sql, args[1]) 431 sql << ')' 432 else 433 raise(InvalidOperation, "invalid operator #{op}") 434 end 435 end
Append literalization of constant to SQL
string.
# File lib/sequel/dataset/sql.rb 438 def constant_sql_append(sql, constant) 439 sql << constant.to_s 440 end
Append literalization of delayed evaluation to SQL
string, causing the delayed evaluation proc to be evaluated.
# File lib/sequel/dataset/sql.rb 444 def delayed_evaluation_sql_append(sql, delay) 445 # Delayed evaluations are used specifically so the SQL 446 # can differ in subsequent calls, so we definitely don't 447 # want to cache the sql in this case. 448 disable_sql_caching! 449 450 if recorder = @opts[:placeholder_literalizer] 451 recorder.use(sql, lambda{delay.call(self)}, nil) 452 else 453 literal_append(sql, delay.call(self)) 454 end 455 end
Append literalization of function call to SQL
string.
# File lib/sequel/dataset/sql.rb 458 def function_sql_append(sql, f) 459 name = f.name 460 opts = f.opts 461 462 if opts[:emulate] 463 if emulate_function?(name) 464 emulate_function_sql_append(sql, f) 465 return 466 end 467 468 name = native_function_name(name) 469 end 470 471 sql << 'LATERAL ' if opts[:lateral] 472 473 case name 474 when SQL::Identifier 475 if supports_quoted_function_names? && opts[:quoted] 476 literal_append(sql, name) 477 else 478 sql << name.value.to_s 479 end 480 when SQL::QualifiedIdentifier 481 if supports_quoted_function_names? && opts[:quoted] != false 482 literal_append(sql, name) 483 else 484 sql << split_qualifiers(name).join('.') 485 end 486 else 487 if supports_quoted_function_names? && opts[:quoted] 488 quote_identifier_append(sql, name) 489 else 490 sql << name.to_s 491 end 492 end 493 494 sql << '(' 495 if filter = opts[:filter] 496 filter = filter_expr(filter, &opts[:filter_block]) 497 end 498 if opts[:*] 499 if filter && !supports_filtered_aggregates? 500 literal_append(sql, Sequel.case({filter=>1}, nil)) 501 filter = nil 502 else 503 sql << '*' 504 end 505 else 506 sql << "DISTINCT " if opts[:distinct] 507 if filter && !supports_filtered_aggregates? 508 expression_list_append(sql, f.args.map{|arg| Sequel.case({filter=>arg}, nil)}) 509 filter = nil 510 else 511 expression_list_append(sql, f.args) 512 end 513 if order = opts[:order] 514 sql << " ORDER BY " 515 expression_list_append(sql, order) 516 end 517 end 518 sql << ')' 519 520 if group = opts[:within_group] 521 sql << " WITHIN GROUP (ORDER BY " 522 expression_list_append(sql, group) 523 sql << ')' 524 end 525 526 if filter 527 sql << " FILTER (WHERE " 528 literal_append(sql, filter) 529 sql << ')' 530 end 531 532 if window = opts[:over] 533 sql << ' OVER ' 534 window_sql_append(sql, window.opts) 535 end 536 537 if opts[:with_ordinality] 538 sql << " WITH ORDINALITY" 539 end 540 end
Append literalization of JOIN clause without ON or USING to SQL
string.
# File lib/sequel/dataset/sql.rb 543 def join_clause_sql_append(sql, jc) 544 table = jc.table 545 table_alias = jc.table_alias 546 table_alias = nil if table == table_alias && !jc.column_aliases 547 sql << ' ' << join_type_sql(jc.join_type) << ' ' 548 identifier_append(sql, table) 549 as_sql_append(sql, table_alias, jc.column_aliases) if table_alias 550 end
Append literalization of JOIN ON clause to SQL
string.
# File lib/sequel/dataset/sql.rb 553 def join_on_clause_sql_append(sql, jc) 554 join_clause_sql_append(sql, jc) 555 sql << ' ON ' 556 literal_append(sql, filter_expr(jc.on)) 557 end
Append literalization of JOIN USING clause to SQL
string.
# File lib/sequel/dataset/sql.rb 560 def join_using_clause_sql_append(sql, jc) 561 join_clause_sql_append(sql, jc) 562 sql << ' USING (' 563 column_list_append(sql, jc.using) 564 sql << ')' 565 end
Append literalization of negative boolean constant to SQL
string.
# File lib/sequel/dataset/sql.rb 568 def negative_boolean_constant_sql_append(sql, constant) 569 sql << 'NOT ' 570 boolean_constant_sql_append(sql, constant) 571 end
Append literalization of ordered expression to SQL
string.
# File lib/sequel/dataset/sql.rb 574 def ordered_expression_sql_append(sql, oe) 575 if emulate = requires_emulating_nulls_first? 576 case oe.nulls 577 when :first 578 null_order = 0 579 when :last 580 null_order = 2 581 end 582 583 if null_order 584 literal_append(sql, Sequel.case({{oe.expression=>nil}=>null_order}, 1)) 585 sql << ", " 586 end 587 end 588 589 literal_append(sql, oe.expression) 590 sql << (oe.descending ? ' DESC' : ' ASC') 591 592 unless emulate 593 case oe.nulls 594 when :first 595 sql << " NULLS FIRST" 596 when :last 597 sql << " NULLS LAST" 598 end 599 end 600 end
Append literalization of placeholder literal string to SQL
string.
# File lib/sequel/dataset/sql.rb 603 def placeholder_literal_string_sql_append(sql, pls) 604 args = pls.args 605 str = pls.str 606 sql << '(' if pls.parens 607 if args.is_a?(Hash) 608 if args.empty? 609 sql << str 610 else 611 re = /:(#{args.keys.map{|k| Regexp.escape(k.to_s)}.join('|')})\b/ 612 while true 613 previous, q, str = str.partition(re) 614 sql << previous 615 literal_append(sql, args[($1||q[1..-1].to_s).to_sym]) unless q.empty? 616 break if str.empty? 617 end 618 end 619 elsif str.is_a?(Array) 620 len = args.length 621 str.each_with_index do |s, i| 622 sql << s 623 literal_append(sql, args[i]) unless i == len 624 end 625 unless str.length == args.length || str.length == args.length + 1 626 raise Error, "Mismatched number of placeholders (#{str.length}) and placeholder arguments (#{args.length}) when using placeholder array" 627 end 628 else 629 i = -1 630 match_len = args.length - 1 631 while true 632 previous, q, str = str.partition('?') 633 sql << previous 634 literal_append(sql, args.at(i+=1)) unless q.empty? 635 if str.empty? 636 unless i == match_len 637 raise Error, "Mismatched number of placeholders (#{i+1}) and placeholder arguments (#{args.length}) when using placeholder string" 638 end 639 break 640 end 641 end 642 end 643 sql << ')' if pls.parens 644 end
Append literalization of qualified identifier to SQL
string. If 3 arguments are given, the 2nd should be the table/qualifier and the third should be column/qualified. If 2 arguments are given, the 2nd should be an SQL::QualifiedIdentifier
.
# File lib/sequel/dataset/sql.rb 649 def qualified_identifier_sql_append(sql, table, column=(c = table.column; table = table.table; c)) 650 identifier_append(sql, table) 651 sql << '.' 652 identifier_append(sql, column) 653 end
Append literalization of unqualified identifier to SQL
string. Adds quoting to identifiers (columns and tables). If identifiers are not being quoted, returns name as a string. If identifiers are being quoted quote the name with quoted_identifier.
# File lib/sequel/dataset/sql.rb 659 def quote_identifier_append(sql, name) 660 if name.is_a?(LiteralString) 661 sql << name 662 else 663 name = name.value if name.is_a?(SQL::Identifier) 664 name = input_identifier(name) 665 if quote_identifiers? 666 quoted_identifier_append(sql, name) 667 else 668 sql << name 669 end 670 end 671 end
Append literalization of identifier or unqualified identifier to SQL
string.
# File lib/sequel/dataset/sql.rb 674 def quote_schema_table_append(sql, table) 675 schema, table = schema_and_table(table) 676 if schema 677 quote_identifier_append(sql, schema) 678 sql << '.' 679 end 680 quote_identifier_append(sql, table) 681 end
Append literalization of quoted identifier to SQL
string. This method quotes the given name with the SQL
standard double quote. should be overridden by subclasses to provide quoting not matching the SQL
standard, such as backtick (used by MySQL
and SQLite
).
# File lib/sequel/dataset/sql.rb 687 def quoted_identifier_append(sql, name) 688 sql << '"' << name.to_s.gsub('"', '""') << '"' 689 end
Split the schema information from the table, returning two strings, one for the schema and one for the table. The returned schema may be nil, but the table will always have a string value.
Note that this function does not handle tables with more than one level of qualification (e.g. database.schema.table on Microsoft SQL
Server).
# File lib/sequel/dataset/sql.rb 698 def schema_and_table(table_name, sch=nil) 699 sch = sch.to_s if sch 700 case table_name 701 when Symbol 702 s, t, _ = split_symbol(table_name) 703 [s||sch, t] 704 when SQL::QualifiedIdentifier 705 [table_name.table.to_s, table_name.column.to_s] 706 when SQL::Identifier 707 [sch, table_name.value.to_s] 708 when String 709 [sch, table_name] 710 else 711 raise Error, 'table_name should be a Symbol, SQL::QualifiedIdentifier, SQL::Identifier, or String' 712 end 713 end
Splits table_name into an array of strings.
ds.split_qualifiers(:s) # ['s'] ds.split_qualifiers(Sequel[:t][:s]) # ['t', 's'] ds.split_qualifiers(Sequel[:d][:t][:s]) # ['d', 't', 's'] ds.split_qualifiers(Sequel.qualify(Sequel[:h][:d], Sequel[:t][:s])) # ['h', 'd', 't', 's']
# File lib/sequel/dataset/sql.rb 721 def split_qualifiers(table_name, *args) 722 case table_name 723 when SQL::QualifiedIdentifier 724 split_qualifiers(table_name.table, nil) + split_qualifiers(table_name.column, nil) 725 else 726 sch, table = schema_and_table(table_name, *args) 727 sch ? [sch, table] : [table] 728 end 729 end
Append literalization of subscripts (SQL
array accesses) to SQL
string.
# File lib/sequel/dataset/sql.rb 732 def subscript_sql_append(sql, s) 733 case s.expression 734 when Symbol, SQL::Subscript, SQL::Identifier, SQL::QualifiedIdentifier 735 # nothing 736 else 737 wrap_expression = true 738 sql << '(' 739 end 740 literal_append(sql, s.expression) 741 if wrap_expression 742 sql << ')[' 743 else 744 sql << '[' 745 end 746 sub = s.sub 747 if sub.length == 1 && (range = sub.first).is_a?(Range) 748 literal_append(sql, range.begin) 749 sql << ':' 750 e = range.end 751 e -= 1 if range.exclude_end? && e.is_a?(Integer) 752 literal_append(sql, e) 753 else 754 expression_list_append(sql, s.sub) 755 end 756 sql << ']' 757 end
Append literalization of windows (for window functions) to SQL
string.
# File lib/sequel/dataset/sql.rb 760 def window_sql_append(sql, opts) 761 raise(Error, 'This dataset does not support window functions') unless supports_window_functions? 762 space = false 763 space_s = ' ' 764 765 sql << '(' 766 767 if window = opts[:window] 768 literal_append(sql, window) 769 space = true 770 end 771 772 if part = opts[:partition] 773 sql << space_s if space 774 sql << "PARTITION BY " 775 expression_list_append(sql, Array(part)) 776 space = true 777 end 778 779 if order = opts[:order] 780 sql << space_s if space 781 sql << "ORDER BY " 782 expression_list_append(sql, Array(order)) 783 space = true 784 end 785 786 if frame = opts[:frame] 787 sql << space_s if space 788 789 if frame.is_a?(String) 790 sql << frame 791 else 792 case frame 793 when :all 794 frame_type = :rows 795 frame_start = :preceding 796 frame_end = :following 797 when :rows, :range, :groups 798 frame_type = frame 799 frame_start = :preceding 800 frame_end = :current 801 when Hash 802 frame_type = frame[:type] 803 unless frame_type == :rows || frame_type == :range || frame_type == :groups 804 raise Error, "invalid window :frame :type option: #{frame_type.inspect}" 805 end 806 unless frame_start = frame[:start] 807 raise Error, "invalid window :frame :start option: #{frame_start.inspect}" 808 end 809 frame_end = frame[:end] 810 frame_exclude = frame[:exclude] 811 else 812 raise Error, "invalid window :frame option: #{frame.inspect}" 813 end 814 815 sql << frame_type.to_s.upcase << " " 816 sql << 'BETWEEN ' if frame_end 817 window_frame_boundary_sql_append(sql, frame_start, :preceding) 818 if frame_end 819 sql << " AND " 820 window_frame_boundary_sql_append(sql, frame_end, :following) 821 end 822 823 if frame_exclude 824 sql << " EXCLUDE " 825 826 case frame_exclude 827 when :current 828 sql << "CURRENT ROW" 829 when :group 830 sql << "GROUP" 831 when :ties 832 sql << "TIES" 833 when :no_others 834 sql << "NO OTHERS" 835 else 836 raise Error, "invalid window :frame :exclude option: #{frame_exclude.inspect}" 837 end 838 end 839 end 840 end 841 842 sql << ')' 843 end
Protected Instance Methods
Return a from_self
dataset if an order or limit is specified, so it works as expected with UNION, EXCEPT, and INTERSECT clauses.
# File lib/sequel/dataset/sql.rb 849 def compound_from_self 850 (@opts[:sql] || @opts[:limit] || @opts[:order] || @opts[:offset]) ? from_self : self 851 end
Private Instance Methods
Internals of the check_*_allowed! methods
# File lib/sequel/dataset/sql.rb 947 def _check_modification_allowed!(modifying_joins_supported) 948 raise(InvalidOperation, "Grouped datasets cannot be modified") if opts[:group] 949 raise(InvalidOperation, "Joined datasets cannot be modified") if !modifying_joins_supported && joined_dataset? 950 end
Formats the truncate statement. Assumes the table given has already been literalized.
# File lib/sequel/dataset/sql.rb 857 def _truncate_sql(table) 858 "TRUNCATE TABLE #{table}" 859 end
Clone of this dataset usable in aggregate operations. Does a from_self
if dataset contains any parameters that would affect normal aggregation, or just removes an existing order if not.
# File lib/sequel/dataset/sql.rb 900 def aggregate_dataset 901 options_overlap(COUNT_FROM_SELF_OPTS) ? from_self : unordered 902 end
Returns an appropriate symbol for the alias represented by s.
# File lib/sequel/dataset/sql.rb 862 def alias_alias_symbol(s) 863 case s 864 when Symbol 865 s 866 when String 867 s.to_sym 868 when SQL::Identifier 869 s.value.to_s.to_sym 870 else 871 raise Error, "Invalid alias for alias_alias_symbol: #{s.inspect}" 872 end 873 end
Returns an appropriate alias symbol for the given object, which can be a Symbol
, String
, SQL::Identifier
, SQL::QualifiedIdentifier
, or SQL::AliasedExpression
.
# File lib/sequel/dataset/sql.rb 878 def alias_symbol(sym) 879 case sym 880 when Symbol 881 s, t, a = split_symbol(sym) 882 a || s ? (a || t).to_sym : sym 883 when String 884 sym.to_sym 885 when SQL::Identifier 886 sym.value.to_s.to_sym 887 when SQL::QualifiedIdentifier 888 alias_symbol(sym.column) 889 when SQL::AliasedExpression 890 alias_alias_symbol(sym.alias) 891 else 892 raise Error, "Invalid alias for alias_symbol: #{sym.inspect}" 893 end 894 end
Append aliasing expression to SQL
string.
# File lib/sequel/dataset/sql.rb 905 def as_sql_append(sql, aliaz, column_aliases=nil) 906 sql << ' AS ' 907 quote_identifier_append(sql, aliaz) 908 if column_aliases 909 raise Error, "#{db.database_type} does not support derived column lists" unless supports_derived_column_lists? 910 sql << '(' 911 identifier_list_append(sql, column_aliases) 912 sql << ')' 913 end 914 end
Don't allow caching SQL
if specifically marked not to.
# File lib/sequel/dataset/sql.rb 917 def cache_sql? 918 !@opts[:no_cache_sql] && !cache_get(:_no_cache_sql) 919 end
Check whether it is allowed to delete from this dataset.
# File lib/sequel/dataset/sql.rb 937 def check_delete_allowed! 938 _check_modification_allowed!(supports_deleting_joins?) 939 end
Check whether it is allowed to insert into this dataset.
# File lib/sequel/dataset/sql.rb 931 def check_insert_allowed! 932 _check_modification_allowed!(false) 933 end
Raise an InvalidOperation exception if modification is not allowed for this dataset. Check whether it is allowed to insert into this dataset. Only for backwards compatibility with older external adapters.
# File lib/sequel/dataset/sql.rb 924 def check_modification_allowed! 925 # SEQUEL6: Remove 926 Sequel::Deprecation.deprecate("Dataset#check_modification_allowed!", "Use check_{insert,delete,update,truncation}_allowed! instead") 927 _check_modification_allowed!(supports_modifying_joins?) 928 end
Raise error if the dataset uses limits or offsets.
# File lib/sequel/dataset/sql.rb 953 def check_not_limited!(type) 954 return if @opts[:skip_limit_check] && type != :truncate 955 raise InvalidOperation, "Dataset##{type} not supported on datasets with limits or offsets" if opts[:limit] || opts[:offset] 956 end
Check whether it is allowed to update this dataset.
# File lib/sequel/dataset/sql.rb 942 def check_update_allowed! 943 _check_modification_allowed!(supports_updating_joins?) 944 end
Append column list to SQL
string. If the column list is empty, a wildcard (*) is appended.
# File lib/sequel/dataset/sql.rb 960 def column_list_append(sql, columns) 961 if (columns.nil? || columns.empty?) 962 sql << '*' 963 else 964 expression_list_append(sql, columns) 965 end 966 end
Yield each pair of arguments to the block, which should return an object representing the SQL
expression for those two arguments. For more than two arguments, the first argument to the block will be result of the previous block call.
# File lib/sequel/dataset/sql.rb 972 def complex_expression_arg_pairs(args) 973 case args.length 974 when 1 975 args[0] 976 when 2 977 yield args[0], args[1] 978 else 979 args.inject{|m, a| yield(m, a)} 980 end 981 end
Append the literalization of the args using complex_expression_arg_pairs
to the given SQL
string, used when database operator/function is 2-ary where Sequel
expression is N-ary.
# File lib/sequel/dataset/sql.rb 986 def complex_expression_arg_pairs_append(sql, args, &block) 987 literal_append(sql, complex_expression_arg_pairs(args, &block)) 988 end
Append literalization of complex expression to SQL
string, for operators unsupported by some databases. Used by adapters for databases that don't support the operators natively.
# File lib/sequel/dataset/sql.rb 993 def complex_expression_emulate_append(sql, op, args) 994 # :nocov: 995 case op 996 # :nocov: 997 when :% 998 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(:MOD, a, b)} 999 when :>> 1000 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel./(a, Sequel.function(:power, 2, b))} 1001 when :<< 1002 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.*(a, Sequel.function(:power, 2, b))} 1003 when :&, :|, :^ 1004 f = BITWISE_METHOD_MAP[op] 1005 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(f, a, b)} 1006 when :'B~' 1007 sql << "((0 - " 1008 literal_append(sql, args[0]) 1009 sql << ") - 1)" 1010 end 1011 end
Append literalization of dataset used in UNION/INTERSECT/EXCEPT clause to SQL
string.
# File lib/sequel/dataset/sql.rb 1014 def compound_dataset_sql_append(sql, ds) 1015 subselect_sql_append(sql, ds) 1016 end
The alias to use for datasets, takes a number to make sure the name is unique.
# File lib/sequel/dataset/sql.rb 1019 def dataset_alias(number) 1020 :"t#{number}" 1021 end
The strftime format to use when literalizing the time.
# File lib/sequel/dataset/sql.rb 1024 def default_timestamp_format 1025 requires_sql_standard_datetimes? ? "TIMESTAMP '%Y-%m-%d %H:%M:%S%N%z'" : "'%Y-%m-%d %H:%M:%S%N%z'" 1026 end
# File lib/sequel/dataset/sql.rb 1028 def delete_delete_sql(sql) 1029 sql << 'DELETE' 1030 end
# File lib/sequel/dataset/sql.rb 1032 def delete_from_sql(sql) 1033 if f = @opts[:from] 1034 sql << ' FROM ' 1035 source_list_append(sql, f) 1036 end 1037 end
Disable caching of SQL
for the current dataset
# File lib/sequel/dataset/sql.rb 1040 def disable_sql_caching! 1041 cache_set(:_no_cache_sql, true) 1042 end
An expression for how to handle an empty array lookup.
# File lib/sequel/dataset/sql.rb 1084 def empty_array_value(op, cols) 1085 {1 => ((op == :IN) ? 0 : 1)} 1086 end
An SQL
FROM clause to use in SELECT statements where the dataset has no from tables.
# File lib/sequel/dataset/sql.rb 1046 def empty_from_sql 1047 nil 1048 end
Whether to emulate the function with the given name. This should only be true if the emulation goes beyond choosing a function with a different name.
# File lib/sequel/dataset/sql.rb 1052 def emulate_function?(name) 1053 false 1054 end
Append literalization of array of expressions to SQL
string, separating them with commas.
# File lib/sequel/dataset/sql.rb 1058 def expression_list_append(sql, columns) 1059 c = false 1060 co = ', ' 1061 columns.each do |col| 1062 sql << co if c 1063 literal_append(sql, col) 1064 c ||= true 1065 end 1066 end
Format the timestamp based on the default_timestamp_format
, with a couple of modifiers. First, allow %N to be used for fractions seconds (if the database supports them), and override %z to always use a numeric offset of hours and minutes.
# File lib/sequel/dataset/sql.rb 1092 def format_timestamp(v) 1093 v2 = db.from_application_timestamp(v) 1094 fmt = default_timestamp_format.gsub(/%[Nz]/) do |m| 1095 if m == '%N' 1096 # Ruby 1.9 supports %N in timestamp formats, but Sequel has supported %N 1097 # for longer in a different way, where the . is already appended and only 6 1098 # decimal places are used by default. 1099 format_timestamp_usec(v.is_a?(DateTime) ? v.sec_fraction*(1000000) : v.usec) if supports_timestamp_usecs? 1100 else 1101 if supports_timestamp_timezones? 1102 # Would like to just use %z format, but it doesn't appear to work on Windows 1103 # Instead, the offset fragment is constructed manually 1104 minutes = (v2.is_a?(DateTime) ? v2.offset * 1440 : v2.utc_offset/60).to_i 1105 format_timestamp_offset(*minutes.divmod(60)) 1106 end 1107 end 1108 end 1109 v2.strftime(fmt) 1110 end
Return the SQL
timestamp fragment to use for the timezone offset.
# File lib/sequel/dataset/sql.rb 1113 def format_timestamp_offset(hour, minute) 1114 sprintf("%+03i%02i", hour, minute) 1115 end
Return the SQL
timestamp fragment to use for the fractional time part. Should start with the decimal point. Uses 6 decimal places by default.
# File lib/sequel/dataset/sql.rb 1119 def format_timestamp_usec(usec, ts=timestamp_precision) 1120 unless ts == 6 1121 usec = usec/(10 ** (6 - ts)) 1122 end 1123 sprintf(".%0#{ts}d", usec) 1124 end
Append literalization of array of grouping elements to SQL
string, seperating them with commas.
# File lib/sequel/dataset/sql.rb 1069 def grouping_element_list_append(sql, columns) 1070 c = false 1071 co = ', ' 1072 columns.each do |col| 1073 sql << co if c 1074 if col.is_a?(Array) && col.empty? 1075 sql << '()' 1076 else 1077 literal_append(sql, Array(col)) 1078 end 1079 c ||= true 1080 end 1081 end
Append literalization of identifier to SQL
string, considering regular strings as SQL
identifiers instead of SQL
strings.
# File lib/sequel/dataset/sql.rb 1128 def identifier_append(sql, v) 1129 if v.is_a?(String) 1130 case v 1131 when LiteralString 1132 sql << v 1133 when SQL::Blob 1134 literal_append(sql, v) 1135 else 1136 quote_identifier_append(sql, v) 1137 end 1138 else 1139 literal_append(sql, v) 1140 end 1141 end
Append literalization of array of identifiers to SQL
string.
# File lib/sequel/dataset/sql.rb 1144 def identifier_list_append(sql, args) 1145 c = false 1146 comma = ', ' 1147 args.each do |a| 1148 sql << comma if c 1149 identifier_append(sql, a) 1150 c ||= true 1151 end 1152 end
Upcase identifiers by default when inputting them into the database.
# File lib/sequel/dataset/sql.rb 1155 def input_identifier(v) 1156 v.to_s.upcase 1157 end
# File lib/sequel/dataset/sql.rb 1168 def insert_columns_sql(sql) 1169 columns = opts[:columns] 1170 if columns && !columns.empty? 1171 sql << ' (' 1172 identifier_list_append(sql, columns) 1173 sql << ')' 1174 end 1175 end
The columns and values to use for an empty insert if the database doesn't support INSERT with DEFAULT
VALUES.
# File lib/sequel/dataset/sql.rb 1179 def insert_empty_columns_values 1180 [[columns.last], [DEFAULT]] 1181 end
# File lib/sequel/dataset/sql.rb 1183 def insert_insert_sql(sql) 1184 sql << "INSERT" 1185 end
# File lib/sequel/dataset/sql.rb 1159 def insert_into_sql(sql) 1160 sql << " INTO " 1161 if (f = @opts[:from]) && f.length == 1 1162 identifier_append(sql, unaliased_identifier(f.first)) 1163 else 1164 source_list_append(sql, f) 1165 end 1166 end
# File lib/sequel/dataset/sql.rb 1206 def insert_returning_sql(sql) 1207 if opts.has_key?(:returning) 1208 sql << " RETURNING " 1209 column_list_append(sql, Array(opts[:returning])) 1210 end 1211 end
# File lib/sequel/dataset/sql.rb 1187 def insert_values_sql(sql) 1188 case values = opts[:values] 1189 when Array 1190 if values.empty? 1191 sql << " DEFAULT VALUES" 1192 else 1193 sql << " VALUES " 1194 literal_append(sql, values) 1195 end 1196 when Dataset 1197 sql << ' ' 1198 subselect_sql_append(sql, values) 1199 when LiteralString 1200 sql << ' ' << values 1201 else 1202 raise Error, "Unsupported INSERT values type, should be an Array or Dataset: #{values.inspect}" 1203 end 1204 end
SQL
fragment specifying a JOIN type, converts underscores to spaces and upcases.
# File lib/sequel/dataset/sql.rb 1217 def join_type_sql(join_type) 1218 "#{join_type.to_s.gsub('_', ' ').upcase} JOIN" 1219 end
Append a literalization of the array to SQL
string. Treats as an expression if an array of all two pairs, or as a SQL
array otherwise.
# File lib/sequel/dataset/sql.rb 1223 def literal_array_append(sql, v) 1224 if Sequel.condition_specifier?(v) 1225 literal_expression_append(sql, SQL::BooleanExpression.from_value_pairs(v)) 1226 else 1227 array_sql_append(sql, v) 1228 end 1229 end
SQL
fragment for BigDecimal
# File lib/sequel/dataset/sql.rb 1232 def literal_big_decimal(v) 1233 d = v.to_s("F") 1234 v.nan? || v.infinite? ? "'#{d}'" : d 1235 end
Append literalization of dataset to SQL
string. Does a subselect inside parantheses.
# File lib/sequel/dataset/sql.rb 1243 def literal_dataset_append(sql, v) 1244 sql << 'LATERAL ' if v.opts[:lateral] 1245 sql << '(' 1246 subselect_sql_append(sql, v) 1247 sql << ')' 1248 end
SQL
fragment for Date, using the ISO8601 format.
# File lib/sequel/dataset/sql.rb 1251 def literal_date(v) 1252 if requires_sql_standard_datetimes? 1253 v.strftime("DATE '%Y-%m-%d'") 1254 else 1255 v.strftime("'%Y-%m-%d'") 1256 end 1257 end
SQL
fragment for DateTime
# File lib/sequel/dataset/sql.rb 1260 def literal_datetime(v) 1261 format_timestamp(v) 1262 end
Append literalization of DateTime to SQL
string.
# File lib/sequel/dataset/sql.rb 1265 def literal_datetime_append(sql, v) 1266 sql << literal_datetime(v) 1267 end
Append literalization of SQL::Expression
to SQL
string.
# File lib/sequel/dataset/sql.rb 1270 def literal_expression_append(sql, v) 1271 v.to_s_append(self, sql) 1272 end
SQL
fragment for false
# File lib/sequel/dataset/sql.rb 1275 def literal_false 1276 "'f'" 1277 end
SQL
fragment for Float
# File lib/sequel/dataset/sql.rb 1280 def literal_float(v) 1281 v.to_s 1282 end
SQL
fragment for Integer
# File lib/sequel/dataset/sql.rb 1290 def literal_integer(v) 1291 v.to_s 1292 end
SQL
fragment for nil
# File lib/sequel/dataset/sql.rb 1295 def literal_nil 1296 "NULL" 1297 end
Append a literalization of the object to the given SQL
string. Calls sql_literal_append
if object responds to it, otherwise calls sql_literal
if object responds to it, otherwise raises an error. If a database specific type is allowed, this should be overriden in a subclass.
# File lib/sequel/dataset/sql.rb 1303 def literal_other_append(sql, v) 1304 # We can't be sure if v will always literalize to the same SQL, so 1305 # don't cache SQL for a dataset that uses this. 1306 disable_sql_caching! 1307 1308 if v.respond_to?(:sql_literal_append) 1309 v.sql_literal_append(self, sql) 1310 elsif v.respond_to?(:sql_literal) 1311 sql << v.sql_literal(self) 1312 else 1313 raise Error, "can't express #{v.inspect} as a SQL literal" 1314 end 1315 end
SQL
fragment for Sequel::SQLTime
, containing just the time part
# File lib/sequel/dataset/sql.rb 1318 def literal_sqltime(v) 1319 v.strftime("'%H:%M:%S#{format_timestamp_usec(v.usec, sqltime_precision) if supports_timestamp_usecs?}'") 1320 end
Append literalization of Sequel::SQLTime
to SQL
string.
# File lib/sequel/dataset/sql.rb 1323 def literal_sqltime_append(sql, v) 1324 sql << literal_sqltime(v) 1325 end
Append literalization of string to SQL
string.
# File lib/sequel/dataset/sql.rb 1328 def literal_string_append(sql, v) 1329 sql << "'" << v.gsub("'", "''") << "'" 1330 end
Append literalization of symbol to SQL
string.
# File lib/sequel/dataset/sql.rb 1333 def literal_symbol_append(sql, v) 1334 c_table, column, c_alias = split_symbol(v) 1335 if c_table 1336 quote_identifier_append(sql, c_table) 1337 sql << '.' 1338 end 1339 quote_identifier_append(sql, column) 1340 as_sql_append(sql, c_alias) if c_alias 1341 end
SQL
fragment for Time
# File lib/sequel/dataset/sql.rb 1344 def literal_time(v) 1345 format_timestamp(v) 1346 end
Append literalization of Time to SQL
string.
# File lib/sequel/dataset/sql.rb 1349 def literal_time_append(sql, v) 1350 sql << literal_time(v) 1351 end
SQL
fragment for true
# File lib/sequel/dataset/sql.rb 1354 def literal_true 1355 "'t'" 1356 end
What strategy to use for import/multi_insert. While SQL-92 defaults to allowing multiple rows in a VALUES clause, there are enough databases that don't allow that that it can't be the default. Use separate queries by default, which works everywhere.
# File lib/sequel/dataset/sql.rb 1362 def multi_insert_sql_strategy 1363 :separate 1364 end
Get the native function name given the emulated function name.
# File lib/sequel/dataset/sql.rb 1368 def native_function_name(emulated_function) 1369 emulated_function 1370 end
Returns a qualified column name (including a table name) if the column name isn't already qualified.
# File lib/sequel/dataset/sql.rb 1374 def qualified_column_name(column, table) 1375 if column.is_a?(Symbol) 1376 c_table, column, _ = split_symbol(column) 1377 unless c_table 1378 case table 1379 when Symbol 1380 schema, table, t_alias = split_symbol(table) 1381 t_alias ||= Sequel::SQL::QualifiedIdentifier.new(schema, table) if schema 1382 when Sequel::SQL::AliasedExpression 1383 t_alias = table.alias 1384 end 1385 c_table = t_alias || table 1386 end 1387 ::Sequel::SQL::QualifiedIdentifier.new(c_table, column) 1388 else 1389 column 1390 end 1391 end
Qualify the given expression to the given table.
# File lib/sequel/dataset/sql.rb 1394 def qualified_expression(e, table) 1395 Qualifier.new(table).transform(e) 1396 end
# File lib/sequel/dataset/sql.rb 1398 def select_columns_sql(sql) 1399 sql << ' ' 1400 column_list_append(sql, @opts[:select]) 1401 end
Modify the sql to add a dataset to the via an EXCEPT, INTERSECT, or UNION clause. This uses a subselect for the compound datasets used, because using parantheses doesn't work on all databases.
# File lib/sequel/dataset/sql.rb 1417 def select_compounds_sql(sql) 1418 return unless c = @opts[:compounds] 1419 c.each do |type, dataset, all| 1420 sql << ' ' << type.to_s.upcase 1421 sql << ' ALL' if all 1422 sql << ' ' 1423 compound_dataset_sql_append(sql, dataset) 1424 end 1425 end
# File lib/sequel/dataset/sql.rb 1403 def select_distinct_sql(sql) 1404 if distinct = @opts[:distinct] 1405 sql << " DISTINCT" 1406 unless distinct.empty? 1407 sql << " ON (" 1408 expression_list_append(sql, distinct) 1409 sql << ')' 1410 end 1411 end 1412 end
# File lib/sequel/dataset/sql.rb 1427 def select_from_sql(sql) 1428 if f = @opts[:from] 1429 sql << ' FROM ' 1430 source_list_append(sql, f) 1431 elsif f = empty_from_sql 1432 sql << f 1433 end 1434 end
# File lib/sequel/dataset/sql.rb 1436 def select_group_sql(sql) 1437 if group = @opts[:group] 1438 sql << " GROUP BY " 1439 if go = @opts[:group_options] 1440 if go == :"grouping sets" 1441 sql << go.to_s.upcase << '(' 1442 grouping_element_list_append(sql, group) 1443 sql << ')' 1444 elsif uses_with_rollup? 1445 expression_list_append(sql, group) 1446 sql << " WITH " << go.to_s.upcase 1447 else 1448 sql << go.to_s.upcase << '(' 1449 expression_list_append(sql, group) 1450 sql << ')' 1451 end 1452 else 1453 expression_list_append(sql, group) 1454 end 1455 end 1456 end
# File lib/sequel/dataset/sql.rb 1458 def select_having_sql(sql) 1459 if having = @opts[:having] 1460 sql << " HAVING " 1461 literal_append(sql, having) 1462 end 1463 end
# File lib/sequel/dataset/sql.rb 1465 def select_join_sql(sql) 1466 if js = @opts[:join] 1467 js.each{|j| literal_append(sql, j)} 1468 end 1469 end
# File lib/sequel/dataset/sql.rb 1471 def select_limit_sql(sql) 1472 if l = @opts[:limit] 1473 sql << " LIMIT " 1474 literal_append(sql, l) 1475 if o = @opts[:offset] 1476 sql << " OFFSET " 1477 literal_append(sql, o) 1478 end 1479 elsif @opts[:offset] 1480 select_only_offset_sql(sql) 1481 end 1482 end
# File lib/sequel/dataset/sql.rb 1484 def select_lock_sql(sql) 1485 case l = @opts[:lock] 1486 when :update 1487 sql << ' FOR UPDATE' 1488 when String 1489 sql << ' ' << l 1490 end 1491 end
Used only if there is an offset and no limit, making it easier to override in the adapter, as many databases do not support just a plain offset with no limit.
# File lib/sequel/dataset/sql.rb 1496 def select_only_offset_sql(sql) 1497 sql << " OFFSET " 1498 literal_append(sql, @opts[:offset]) 1499 end
# File lib/sequel/dataset/sql.rb 1501 def select_order_sql(sql) 1502 if o = @opts[:order] 1503 sql << " ORDER BY " 1504 expression_list_append(sql, o) 1505 end 1506 end
# File lib/sequel/dataset/sql.rb 1510 def select_select_sql(sql) 1511 sql << 'SELECT' 1512 end
# File lib/sequel/dataset/sql.rb 1514 def select_where_sql(sql) 1515 if w = @opts[:where] 1516 sql << " WHERE " 1517 literal_append(sql, w) 1518 end 1519 end
# File lib/sequel/dataset/sql.rb 1523 def select_window_sql(sql) 1524 if ws = @opts[:window] 1525 sql << " WINDOW " 1526 c = false 1527 co = ', ' 1528 as = ' AS ' 1529 ws.map do |name, window| 1530 sql << co if c 1531 literal_append(sql, name) 1532 sql << as 1533 literal_append(sql, window) 1534 c ||= true 1535 end 1536 end 1537 end
# File lib/sequel/dataset/sql.rb 1539 def select_with_sql(sql) 1540 return unless supports_cte? 1541 ws = opts[:with] 1542 return if !ws || ws.empty? 1543 sql << select_with_sql_base 1544 c = false 1545 comma = ', ' 1546 ws.each do |w| 1547 sql << comma if c 1548 select_with_sql_prefix(sql, w) 1549 literal_dataset_append(sql, w[:dataset]) 1550 c ||= true 1551 end 1552 sql << ' ' 1553 end
# File lib/sequel/dataset/sql.rb 1558 def select_with_sql_base 1559 "WITH " 1560 end
# File lib/sequel/dataset/sql.rb 1562 def select_with_sql_prefix(sql, w) 1563 quote_identifier_append(sql, w[:name]) 1564 if args = w[:args] 1565 sql << '(' 1566 identifier_list_append(sql, args) 1567 sql << ')' 1568 end 1569 sql << ' AS ' 1570 end
Whether the symbol cache should be skipped when literalizing the dataset
# File lib/sequel/dataset/sql.rb 1573 def skip_symbol_cache? 1574 @opts[:skip_symbol_cache] 1575 end
Append literalization of array of sources/tables to SQL
string, raising an Error
if there are no sources.
# File lib/sequel/dataset/sql.rb 1579 def source_list_append(sql, sources) 1580 raise(Error, 'No source specified for query') if sources.nil? || sources == [] 1581 identifier_list_append(sql, sources) 1582 end
Delegate to Sequel.split_symbol.
# File lib/sequel/dataset/sql.rb 1585 def split_symbol(sym) 1586 Sequel.split_symbol(sym) 1587 end
The string that is appended to to create the SQL
query, the empty string by default.
# File lib/sequel/dataset/sql.rb 1591 def sql_string_origin 1592 String.new 1593 end
The precision to use for SQLTime
instances (time column values without dates). Defaults to timestamp_precision.
# File lib/sequel/dataset/sql.rb 1597 def sqltime_precision 1598 timestamp_precision 1599 end
SQL
to use if this dataset uses static SQL
. Since static SQL
can be a PlaceholderLiteralString in addition to a String
, we literalize nonstrings. If there is an append_sql for this dataset, append to that SQL
instead of returning the value.
# File lib/sequel/dataset/sql.rb 1605 def static_sql(sql) 1606 if append_sql = @opts[:append_sql] 1607 if sql.is_a?(String) 1608 append_sql << sql 1609 else 1610 literal_append(append_sql, sql) 1611 end 1612 else 1613 if sql.is_a?(String) 1614 sql 1615 else 1616 literal(sql) 1617 end 1618 end 1619 end
Append literalization of the subselect to SQL
string.
# File lib/sequel/dataset/sql.rb 1622 def subselect_sql_append(sql, ds) 1623 sds = subselect_sql_dataset(sql, ds) 1624 sds.sql 1625 unless sds.send(:cache_sql?) 1626 # If subquery dataset does not allow caching SQL, 1627 # then this dataset should not allow caching SQL. 1628 disable_sql_caching! 1629 end 1630 end
# File lib/sequel/dataset/sql.rb 1632 def subselect_sql_dataset(sql, ds) 1633 ds.clone(:append_sql=>sql) 1634 end
The number of decimal digits of precision to use in timestamps.
# File lib/sequel/dataset/sql.rb 1637 def timestamp_precision 1638 supports_timestamp_usecs? ? 6 : 0 1639 end
# File lib/sequel/dataset/sql.rb 1647 def update_set_sql(sql) 1648 sql << ' SET ' 1649 values = @opts[:values] 1650 if values.is_a?(Hash) 1651 update_sql_values_hash(sql, values) 1652 else 1653 sql << values 1654 end 1655 end
# File lib/sequel/dataset/sql.rb 1657 def update_sql_values_hash(sql, values) 1658 c = false 1659 eq = ' = ' 1660 values.each do |k, v| 1661 sql << ', ' if c 1662 if k.is_a?(String) && !k.is_a?(LiteralString) 1663 quote_identifier_append(sql, k) 1664 else 1665 literal_append(sql, k) 1666 end 1667 sql << eq 1668 literal_append(sql, v) 1669 c ||= true 1670 end 1671 end
# File lib/sequel/dataset/sql.rb 1641 def update_table_sql(sql) 1642 sql << ' ' 1643 source_list_append(sql, @opts[:from]) 1644 select_join_sql(sql) if supports_modifying_joins? 1645 end
# File lib/sequel/dataset/sql.rb 1673 def update_update_sql(sql) 1674 sql << 'UPDATE' 1675 end
# File lib/sequel/dataset/sql.rb 1677 def window_frame_boundary_sql_append(sql, boundary, direction) 1678 case boundary 1679 when :current 1680 sql << "CURRENT ROW" 1681 when :preceding 1682 sql << "UNBOUNDED PRECEDING" 1683 when :following 1684 sql << "UNBOUNDED FOLLOWING" 1685 else 1686 if boundary.is_a?(Array) 1687 offset, direction = boundary 1688 unless boundary.length == 2 && (direction == :preceding || direction == :following) 1689 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1690 end 1691 else 1692 offset = boundary 1693 end 1694 1695 case offset 1696 when Numeric, String, SQL::Cast 1697 # nothing 1698 else 1699 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1700 end 1701 1702 literal_append(sql, offset) 1703 sql << (direction == :preceding ? " PRECEDING" : " FOLLOWING") 1704 end 1705 end