module Sequel::SQLite::DatabaseMethods

No matter how you connect to SQLite, the following Database options can be used to set PRAGMAs on connections in a thread-safe manner: :auto_vacuum, :foreign_keys, :synchronous, and :temp_store.

Constants

AUTO_VACUUM
DATABASE_ERROR_REGEXPS
SYNCHRONOUS
TEMP_STORE
TRANSACTION_MODE

Attributes

current_timestamp_utc[RW]

Whether to keep CURRENT_TIMESTAMP and similar expressions in UTC. By default, the expressions are converted to localtime.

integer_booleans[RW]

Whether to use integers for booleans in the database. SQLite recommends booleans be stored as integers, but historically Sequel has used 't'/'f'.

transaction_mode[R]

A symbol signifying the value of the default transaction mode

use_timestamp_timezones[W]

Override the default setting for whether to use timezones in timestamps. It is set to false by default, as SQLite's date/time methods do not support timezones in timestamps.

Public Instance Methods

database_type() click to toggle source

SQLite uses the :sqlite database type.

   # File lib/sequel/adapters/shared/sqlite.rb
58 def database_type
59   :sqlite
60 end
foreign_key_list(table, opts=OPTS) click to toggle source

Return the array of foreign key info hashes using the foreign_key_list PRAGMA, including information for the :on_update and :on_delete entries.

   # File lib/sequel/adapters/shared/sqlite.rb
69 def foreign_key_list(table, opts=OPTS)
70   m = output_identifier_meth
71   h = {}
72   _foreign_key_list_ds(table).each do |row|
73     if r = h[row[:id]]
74       r[:columns] << m.call(row[:from])
75       r[:key] << m.call(row[:to]) if r[:key]
76     else
77       h[row[:id]] = {:columns=>[m.call(row[:from])], :table=>m.call(row[:table]), :key=>([m.call(row[:to])] if row[:to]), :on_update=>on_delete_sql_to_sym(row[:on_update]), :on_delete=>on_delete_sql_to_sym(row[:on_delete])}
78     end
79   end
80   h.values
81 end
freeze() click to toggle source
Calls superclass method
   # File lib/sequel/adapters/shared/sqlite.rb
83 def freeze
84   sqlite_version
85   use_timestamp_timezones?
86   super
87 end
indexes(table, opts=OPTS) click to toggle source

Use the index_list and index_info PRAGMAs to determine the indexes on the table.

    # File lib/sequel/adapters/shared/sqlite.rb
 90 def indexes(table, opts=OPTS)
 91   m = output_identifier_meth
 92   im = input_identifier_meth
 93   indexes = {}
 94   table = table.value if table.is_a?(Sequel::SQL::Identifier)
 95   metadata_dataset.with_sql("PRAGMA index_list(?)", im.call(table)).each do |r|
 96     if opts[:only_autocreated]
 97       # If specifically asked for only autocreated indexes, then return those an only those
 98       next unless r[:name] =~ /\Asqlite_autoindex_/
 99     elsif r.has_key?(:origin)
100       # If origin is set, then only exclude primary key indexes and partial indexes
101       next if r[:origin] == 'pk'
102       next if r[:partial].to_i == 1
103     else
104       # When :origin key not present, assume any autoindex could be a primary key one and exclude it
105       next if r[:name] =~ /\Asqlite_autoindex_/
106     end
107 
108     indexes[m.call(r[:name])] = {:unique=>r[:unique].to_i==1}
109   end
110   indexes.each do |k, v|
111     v[:columns] = metadata_dataset.with_sql("PRAGMA index_info(?)", im.call(k)).map(:name).map{|x| m.call(x)}
112   end
113   indexes
114 end
set_integer_booleans() click to toggle source

Set the integer_booleans option using the passed in :integer_boolean option.

   # File lib/sequel/adapters/shared/sqlite.rb
63 def set_integer_booleans
64   @integer_booleans = @opts.has_key?(:integer_booleans) ? typecast_value_boolean(@opts[:integer_booleans]) : true
65 end
sqlite_version() click to toggle source

The version of the server as an integer, where 3.6.19 = 30619. If the server version can't be determined, 0 is used.

    # File lib/sequel/adapters/shared/sqlite.rb
118 def sqlite_version
119   return @sqlite_version if defined?(@sqlite_version)
120   @sqlite_version = begin
121     v = fetch('SELECT sqlite_version()').single_value
122     [10000, 100, 1].zip(v.split('.')).inject(0){|a, m| a + m[0] * Integer(m[1])}
123   rescue
124     0
125   end
126 end
supports_create_table_if_not_exists?() click to toggle source

SQLite supports CREATE TABLE IF NOT EXISTS syntax since 3.3.0.

    # File lib/sequel/adapters/shared/sqlite.rb
129 def supports_create_table_if_not_exists?
130   sqlite_version >= 30300
131 end
supports_deferrable_foreign_key_constraints?() click to toggle source

SQLite 3.6.19+ supports deferrable foreign key constraints.

    # File lib/sequel/adapters/shared/sqlite.rb
134 def supports_deferrable_foreign_key_constraints?
135   sqlite_version >= 30619
136 end
supports_partial_indexes?() click to toggle source

SQLite 3.8.0+ supports partial indexes.

    # File lib/sequel/adapters/shared/sqlite.rb
139 def supports_partial_indexes?
140   sqlite_version >= 30800
141 end
supports_savepoints?() click to toggle source

SQLite 3.6.8+ supports savepoints.

    # File lib/sequel/adapters/shared/sqlite.rb
144 def supports_savepoints?
145   sqlite_version >= 30608
146 end
tables(opts=OPTS) click to toggle source

Array of symbols specifying the table names in the current database.

Options:

:server

Set the server to use.

    # File lib/sequel/adapters/shared/sqlite.rb
163 def tables(opts=OPTS)
164   tables_and_views(Sequel.~(:name=>'sqlite_sequence') & {:type => 'table'}, opts)
165 end
transaction_mode=(value) click to toggle source

Set the default transaction mode.

   # File lib/sequel/adapters/shared/sqlite.rb
49 def transaction_mode=(value)
50   if TRANSACTION_MODE.include?(value)
51     @transaction_mode = value
52   else
53     raise Error, "Invalid value for transaction_mode.  Please specify one of :deferred, :immediate, :exclusive, nil"
54   end
55 end
use_timestamp_timezones?() click to toggle source

SQLite supports timezones in timestamps, since it just stores them as strings, but it breaks the usage of SQLite's datetime functions.

    # File lib/sequel/adapters/shared/sqlite.rb
155 def use_timestamp_timezones?
156   defined?(@use_timestamp_timezones) ? @use_timestamp_timezones : (@use_timestamp_timezones = false)
157 end
values(v) click to toggle source

Creates a dataset that uses the VALUES clause:

DB.values([[1, 2], [3, 4]])
# VALUES ((1, 2), (3, 4))
    # File lib/sequel/adapters/shared/sqlite.rb
171 def values(v)
172   @default_dataset.clone(:values=>v)
173 end
views(opts=OPTS) click to toggle source

Array of symbols specifying the view names in the current database.

Options:

:server

Set the server to use.

    # File lib/sequel/adapters/shared/sqlite.rb
179 def views(opts=OPTS)
180   tables_and_views({:type => 'view'}, opts)
181 end

Private Instance Methods

_foreign_key_list_ds(table) click to toggle source

Dataset used for parsing foreign key lists

    # File lib/sequel/adapters/shared/sqlite.rb
186 def _foreign_key_list_ds(table)
187   metadata_dataset.with_sql("PRAGMA foreign_key_list(?)", input_identifier_meth.call(table))
188 end
_parse_pragma_ds(table_name, opts) click to toggle source

Dataset used for parsing schema

    # File lib/sequel/adapters/shared/sqlite.rb
191 def _parse_pragma_ds(table_name, opts)
192   metadata_dataset.with_sql("PRAGMA table_#{'x' if sqlite_version > 33100}info(?)", input_identifier_meth(opts[:dataset]).call(table_name))
193 end
alter_table_sql(table, op) click to toggle source

SQLite supports limited table modification. You can add a column or an index. Dropping columns is supported by copying the table into a temporary table, dropping the table, and creating a new table without the column inside of a transaction.

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
231 def alter_table_sql(table, op)
232   case op[:op]
233   when :add_index, :drop_index
234     super
235   when :add_column
236     if op[:unique] || op[:primary_key]
237       duplicate_table(table){|columns| columns.push(op)}
238     else
239       super
240     end
241   when :drop_column
242     if sqlite_version >= 33500
243       super
244     else
245       ocp = lambda{|oc| oc.delete_if{|c| c.to_s == op[:name].to_s}}
246       duplicate_table(table, :old_columns_proc=>ocp){|columns| columns.delete_if{|s| s[:name].to_s == op[:name].to_s}}
247     end
248   when :rename_column
249     if sqlite_version >= 32500
250       super
251     else
252       ncp = lambda{|nc| nc.map!{|c| c.to_s == op[:name].to_s ? op[:new_name] : c}}
253       duplicate_table(table, :new_columns_proc=>ncp){|columns| columns.each{|s| s[:name] = op[:new_name] if s[:name].to_s == op[:name].to_s}}
254     end
255   when :set_column_default
256     duplicate_table(table){|columns| columns.each{|s| s[:default] = op[:default] if s[:name].to_s == op[:name].to_s}}
257   when :set_column_null
258     duplicate_table(table){|columns| columns.each{|s| s[:null] = op[:null] if s[:name].to_s == op[:name].to_s}}
259   when :set_column_type
260     duplicate_table(table){|columns| columns.each{|s| s.merge!(op) if s[:name].to_s == op[:name].to_s}}
261   when :drop_constraint
262     case op[:type]
263     when :primary_key
264       duplicate_table(table) do |columns|
265         columns.each do |s|
266           s[:unique] = false if s[:primary_key]
267           s[:primary_key] = s[:auto_increment] = nil
268         end
269       end
270     when :foreign_key
271       if op[:columns]
272         duplicate_table(table, :skip_foreign_key_columns=>op[:columns])
273       else
274         duplicate_table(table, :no_foreign_keys=>true)
275       end
276     when :unique
277       duplicate_table(table, :no_unique=>true)
278     else
279       duplicate_table(table)
280     end
281   when :add_constraint
282     duplicate_table(table, :constraints=>[op])
283   when :add_constraints
284     duplicate_table(table, :constraints=>op[:ops])
285   else
286     raise Error, "Unsupported ALTER TABLE operation: #{op[:op].inspect}"
287   end
288 end
apply_alter_table(table, ops) click to toggle source

Run all alter_table commands in a transaction. This is technically only needed for drop column.

    # File lib/sequel/adapters/shared/sqlite.rb
197 def apply_alter_table(table, ops)
198   fks = fetch("PRAGMA foreign_keys")
199   if fks
200     run "PRAGMA foreign_keys = 0"
201     run "PRAGMA legacy_alter_table = 1" if sqlite_version >= 32600
202   end
203   transaction do 
204     if ops.length > 1 && ops.all?{|op| op[:op] == :add_constraint || op[:op] == :set_column_null}
205       null_ops, ops = ops.partition{|op| op[:op] == :set_column_null}
206 
207       # Apply NULL/NOT NULL ops first, since those should be purely idependent of the constraints.
208       null_ops.each{|op| alter_table_sql_list(table, [op]).flatten.each{|sql| execute_ddl(sql)}}
209 
210       # If you are just doing constraints, apply all of them at the same time,
211       # as otherwise all but the last one get lost.
212       alter_table_sql_list(table, [{:op=>:add_constraints, :ops=>ops}]).flatten.each{|sql| execute_ddl(sql)}
213     else
214       # Run each operation separately, as later operations may depend on the
215       # results of earlier operations.
216       ops.each{|op| alter_table_sql_list(table, [op]).flatten.each{|sql| execute_ddl(sql)}}
217     end
218   end
219   remove_cached_schema(table)
220 ensure
221   if fks
222     run "PRAGMA foreign_keys = 1"
223     run "PRAGMA legacy_alter_table = 0" if sqlite_version >= 32600
224   end
225 end
backup_table_name(table, opts=OPTS) click to toggle source

A name to use for the backup table

    # File lib/sequel/adapters/shared/sqlite.rb
298 def backup_table_name(table, opts=OPTS)
299   table = table.gsub('`', '')
300   (opts[:times]||1000).times do |i|
301     table_name = "#{table}_backup#{i}"
302     return table_name unless table_exists?(table_name)
303   end
304 end
begin_new_transaction(conn, opts) click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
290 def begin_new_transaction(conn, opts)
291   mode = opts[:mode] || @transaction_mode
292   sql = TRANSACTION_MODE[mode] or raise Error, "transaction :mode must be one of: :deferred, :immediate, :exclusive, nil"
293   log_connection_execute(conn, sql)
294   set_transaction_isolation(conn, opts)
295 end
can_add_primary_key_constraint_on_nullable_columns?() click to toggle source

SQLite allows adding primary key constraints on NULLABLE columns, but then does not enforce NOT NULL for such columns, so force setting the columns NOT NULL.

    # File lib/sequel/adapters/shared/sqlite.rb
308 def can_add_primary_key_constraint_on_nullable_columns?
309   false
310 end
column_definition_default_sql(sql, column) click to toggle source

Surround default with parens to appease SQLite. Add support for GENERATED ALWAYS AS.

    # File lib/sequel/adapters/shared/sqlite.rb
313 def column_definition_default_sql(sql, column)
314   sql << " DEFAULT (#{literal(column[:default])})" if column.include?(:default)
315   if (generated = column[:generated_always_as])
316     if (generated_type = column[:generated_type]) && (generated_type == :stored || generated_type == :virtual)
317       generated_type = generated_type.to_s.upcase
318     end
319     sql << " GENERATED ALWAYS AS (#{literal(generated)}) #{generated_type}"
320   end
321 end
column_schema_integer_min_max_values(db_type) click to toggle source

SQLite does not restrict the integer type to a specific range.

    # File lib/sequel/adapters/shared/sqlite.rb
324 def column_schema_integer_min_max_values(db_type)
325   nil
326 end
connection_pragmas() click to toggle source

Array of PRAGMA SQL statements based on the Database options that should be applied to new connections.

    # File lib/sequel/adapters/shared/sqlite.rb
330 def connection_pragmas
331   ps = []
332   v = typecast_value_boolean(opts.fetch(:foreign_keys, 1))
333   ps << "PRAGMA foreign_keys = #{v ? 1 : 0}"
334   v = typecast_value_boolean(opts.fetch(:case_sensitive_like, 1))
335   ps << "PRAGMA case_sensitive_like = #{v ? 1 : 0}"
336   [[:auto_vacuum, AUTO_VACUUM], [:synchronous, SYNCHRONOUS], [:temp_store, TEMP_STORE]].each do |prag, con|
337     if v = opts[prag]
338       raise(Error, "Value for PRAGMA #{prag} not supported, should be one of #{con.join(', ')}") unless v = con.index(v.to_sym)
339       ps << "PRAGMA #{prag} = #{v}"
340     end
341   end
342   ps
343 end
create_table_sql(name, generator, options) click to toggle source

Support creating STRICT tables via :strict option

    # File lib/sequel/adapters/shared/sqlite.rb
346 def create_table_sql(name, generator, options)
347   "#{super}#{' STRICT' if options[:strict]}"
348 end
create_view_prefix_sql(name, options) click to toggle source

SQLite support creating temporary views.

    # File lib/sequel/adapters/shared/sqlite.rb
351 def create_view_prefix_sql(name, options)
352   create_view_sql_append_columns("CREATE #{'TEMPORARY 'if options[:temp]}VIEW #{quote_schema_table(name)}", options[:columns])
353 end
database_error_regexps() click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
364 def database_error_regexps
365   DATABASE_ERROR_REGEXPS
366 end
database_specific_error_class(exception, opts) click to toggle source

Recognize SQLite error codes if the exception provides access to them.

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
369 def database_specific_error_class(exception, opts)
370   case sqlite_error_code(exception)
371   when 1299
372     NotNullConstraintViolation
373   when 1555, 2067, 2579
374     UniqueConstraintViolation
375   when 787
376     ForeignKeyConstraintViolation
377   when 275
378     CheckConstraintViolation
379   when 19
380     ConstraintViolation
381   when 517
382     SerializationFailure
383   else
384     super
385   end
386 end
defined_columns_for(table) click to toggle source

The array of column schema hashes for the current columns in the table

    # File lib/sequel/adapters/shared/sqlite.rb
389 def defined_columns_for(table)
390   cols = parse_pragma(table, OPTS)
391   cols.each do |c|
392     c[:default] = LiteralString.new(c[:default]) if c[:default]
393     c[:type] = c[:db_type]
394   end
395   cols
396 end
duplicate_table(table, opts=OPTS) { |def_columns| ... } click to toggle source

Duplicate an existing table by creating a new table, copying all records from the existing table into the new table, deleting the existing table and renaming the new table to the existing table's name.

    # File lib/sequel/adapters/shared/sqlite.rb
401 def duplicate_table(table, opts=OPTS)
402   remove_cached_schema(table)
403   def_columns = defined_columns_for(table)
404   old_columns = def_columns.map{|c| c[:name]}
405   opts[:old_columns_proc].call(old_columns) if opts[:old_columns_proc]
406 
407   yield def_columns if defined?(yield)
408 
409   constraints = (opts[:constraints] || []).dup
410   pks = []
411   def_columns.each{|c| pks << c[:name] if c[:primary_key]}
412   if pks.length > 1
413     constraints << {:type=>:primary_key, :columns=>pks}
414     def_columns.each{|c| c[:primary_key] = false if c[:primary_key]}
415   end
416 
417   # If dropping a foreign key constraint, drop all foreign key constraints,
418   # as there is no way to determine which one to drop.
419   unless opts[:no_foreign_keys]
420     fks = foreign_key_list(table)
421 
422     # If dropping a column, if there is a foreign key with that
423     # column, don't include it when building a copy of the table.
424     if ocp = opts[:old_columns_proc]
425       fks.delete_if{|c| ocp.call(c[:columns].dup) != c[:columns]}
426     end
427     
428     # Skip any foreign key columns where a constraint for those
429     # foreign keys is being dropped.
430     if sfkc = opts[:skip_foreign_key_columns]
431       fks.delete_if{|c| c[:columns] == sfkc}
432     end
433 
434     constraints.concat(fks.each{|h| h[:type] = :foreign_key})
435   end
436 
437   # Determine unique constraints and make sure the new columns have them
438   unique_columns = []
439   skip_indexes = []
440   indexes(table, :only_autocreated=>true).each do |name, h|
441     skip_indexes << name
442     if h[:unique] && !opts[:no_unique]
443       if h[:columns].length == 1
444         unique_columns.concat(h[:columns])
445       elsif h[:columns].map(&:to_s) != pks
446         constraints << {:type=>:unique, :columns=>h[:columns]}
447       end
448     end
449   end
450   unique_columns -= pks
451   unless unique_columns.empty?
452     unique_columns.map!{|c| quote_identifier(c)}
453     def_columns.each do |c|
454       c[:unique] = true if unique_columns.include?(quote_identifier(c[:name])) && c[:unique] != false
455     end
456   end
457   
458   def_columns_str = (def_columns.map{|c| column_definition_sql(c)} + constraints.map{|c| constraint_definition_sql(c)}).join(', ')
459   new_columns = old_columns.dup
460   opts[:new_columns_proc].call(new_columns) if opts[:new_columns_proc]
461 
462   qt = quote_schema_table(table)
463   bt = quote_identifier(backup_table_name(qt))
464   a = [
465      "ALTER TABLE #{qt} RENAME TO #{bt}",
466      "CREATE TABLE #{qt}(#{def_columns_str})",
467      "INSERT INTO #{qt}(#{dataset.send(:identifier_list, new_columns)}) SELECT #{dataset.send(:identifier_list, old_columns)} FROM #{bt}",
468      "DROP TABLE #{bt}"
469   ]
470   indexes(table).each do |name, h|
471     next if skip_indexes.include?(name)
472     if (h[:columns].map(&:to_s) - new_columns).empty?
473       a << alter_table_sql(table, h.merge(:op=>:add_index, :name=>name))
474     end
475   end
476   a
477 end
on_delete_sql_to_sym(str) click to toggle source

Does the reverse of on_delete_clause, eg. converts strings like +'SET NULL'+ to symbols :set_null.

    # File lib/sequel/adapters/shared/sqlite.rb
481 def on_delete_sql_to_sym(str)
482   case str
483   when 'RESTRICT'
484     :restrict
485   when 'CASCADE'
486     :cascade
487   when 'SET NULL'
488     :set_null
489   when 'SET DEFAULT'
490     :set_default
491   when 'NO ACTION'
492     :no_action
493   end
494 end
parse_pragma(table_name, opts) click to toggle source

Parse the output of the table_info pragma

    # File lib/sequel/adapters/shared/sqlite.rb
497 def parse_pragma(table_name, opts)
498   pks = 0
499   sch = _parse_pragma_ds(table_name, opts).map do |row|
500     if sqlite_version > 33100
501       # table_xinfo PRAGMA used, remove hidden columns
502       # that are not generated columns
503       if row[:generated] = (row.delete(:hidden) != 0)
504         next unless row[:type].end_with?(' GENERATED ALWAYS')
505         row[:type] = row[:type].sub(' GENERATED ALWAYS', '')
506       end
507     end
508 
509     row.delete(:cid)
510     row[:allow_null] = row.delete(:notnull).to_i == 0
511     row[:default] = row.delete(:dflt_value)
512     row[:default] = nil if blank_object?(row[:default]) || row[:default] == 'NULL'
513     row[:db_type] = row.delete(:type)
514     if row[:primary_key] = row.delete(:pk).to_i > 0
515       pks += 1
516       # Guess that an integer primary key uses auto increment,
517       # since that is Sequel's default and SQLite does not provide
518       # a way to introspect whether it is actually autoincrementing.
519       row[:auto_increment] = row[:db_type].downcase == 'integer'
520     end
521     row[:type] = schema_column_type(row[:db_type])
522     row
523   end
524 
525   sch.compact!
526 
527   if pks > 1
528     # SQLite does not allow use of auto increment for tables
529     # with composite primary keys, so remove auto_increment
530     # if composite primary keys are detected.
531     sch.each{|r| r.delete(:auto_increment)}
532   end
533 
534   sch
535 end
schema_parse_table(table_name, opts) click to toggle source

SQLite supports schema parsing using the table_info PRAGMA, so parse the output of that into the format Sequel expects.

    # File lib/sequel/adapters/shared/sqlite.rb
539 def schema_parse_table(table_name, opts)
540   m = output_identifier_meth(opts[:dataset])
541   parse_pragma(table_name, opts).map do |row|
542     [m.call(row.delete(:name)), row]
543   end
544 end
sqlite_error_code(exception) click to toggle source

Don't support SQLite error codes for exceptions by default.

    # File lib/sequel/adapters/shared/sqlite.rb
547 def sqlite_error_code(exception)
548   nil
549 end
tables_and_views(filter, opts) click to toggle source

Backbone of the tables and views support.

    # File lib/sequel/adapters/shared/sqlite.rb
552 def tables_and_views(filter, opts)
553   m = output_identifier_meth
554   metadata_dataset.from(:sqlite_master).server(opts[:server]).where(filter).map{|r| m.call(r[:name])}
555 end
type_literal_generic_bignum_symbol(column) click to toggle source

SQLite only supports AUTOINCREMENT on integer columns, not bigint columns, so use integer instead of bigint for those columns.

Calls superclass method
    # File lib/sequel/adapters/shared/sqlite.rb
560 def type_literal_generic_bignum_symbol(column)
561   column[:auto_increment] ? :integer : super
562 end