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     ocp = lambda{|oc| oc.delete_if{|c| c.to_s == op[:name].to_s}}
243     duplicate_table(table, :old_columns_proc=>ocp){|columns| columns.delete_if{|s| s[:name].to_s == op[:name].to_s}}
244   when :rename_column
245     if sqlite_version >= 32500
246       super
247     else
248       ncp = lambda{|nc| nc.map!{|c| c.to_s == op[:name].to_s ? op[:new_name] : c}}
249       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}}
250     end
251   when :set_column_default
252     duplicate_table(table){|columns| columns.each{|s| s[:default] = op[:default] if s[:name].to_s == op[:name].to_s}}
253   when :set_column_null
254     duplicate_table(table){|columns| columns.each{|s| s[:null] = op[:null] if s[:name].to_s == op[:name].to_s}}
255   when :set_column_type
256     duplicate_table(table){|columns| columns.each{|s| s.merge!(op) if s[:name].to_s == op[:name].to_s}}
257   when :drop_constraint
258     case op[:type]
259     when :primary_key
260       duplicate_table(table) do |columns|
261         columns.each do |s|
262           s[:unique] = false if s[:primary_key]
263           s[:primary_key] = s[:auto_increment] = nil
264         end
265       end
266     when :foreign_key
267       if op[:columns]
268         duplicate_table(table, :skip_foreign_key_columns=>op[:columns])
269       else
270         duplicate_table(table, :no_foreign_keys=>true)
271       end
272     when :unique
273       duplicate_table(table, :no_unique=>true)
274     else
275       duplicate_table(table)
276     end
277   when :add_constraint
278     duplicate_table(table, :constraints=>[op])
279   when :add_constraints
280     duplicate_table(table, :constraints=>op[:ops])
281   else
282     raise Error, "Unsupported ALTER TABLE operation: #{op[:op].inspect}"
283   end
284 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
294 def backup_table_name(table, opts=OPTS)
295   table = table.gsub('`', '')
296   (opts[:times]||1000).times do |i|
297     table_name = "#{table}_backup#{i}"
298     return table_name unless table_exists?(table_name)
299   end
300 end
begin_new_transaction(conn, opts) click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
286 def begin_new_transaction(conn, opts)
287   mode = opts[:mode] || @transaction_mode
288   sql = TRANSACTION_MODE[mode] or raise Error, "transaction :mode must be one of: :deferred, :immediate, :exclusive, nil"
289   log_connection_execute(conn, sql)
290   set_transaction_isolation(conn, opts)
291 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
304 def can_add_primary_key_constraint_on_nullable_columns?
305   false
306 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
309 def column_definition_default_sql(sql, column)
310   sql << " DEFAULT (#{literal(column[:default])})" if column.include?(:default)
311   if (generated = column[:generated_always_as])
312     if (generated_type = column[:generated_type]) && (generated_type == :stored || generated_type == :virtual)
313       generated_type = generated_type.to_s.upcase
314     end
315     sql << " GENERATED ALWAYS AS (#{literal(generated)}) #{generated_type}"
316   end
317 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
321 def connection_pragmas
322   ps = []
323   v = typecast_value_boolean(opts.fetch(:foreign_keys, 1))
324   ps << "PRAGMA foreign_keys = #{v ? 1 : 0}"
325   v = typecast_value_boolean(opts.fetch(:case_sensitive_like, 1))
326   ps << "PRAGMA case_sensitive_like = #{v ? 1 : 0}"
327   [[:auto_vacuum, AUTO_VACUUM], [:synchronous, SYNCHRONOUS], [:temp_store, TEMP_STORE]].each do |prag, con|
328     if v = opts[prag]
329       raise(Error, "Value for PRAGMA #{prag} not supported, should be one of #{con.join(', ')}") unless v = con.index(v.to_sym)
330       ps << "PRAGMA #{prag} = #{v}"
331     end
332   end
333   ps
334 end
create_view_prefix_sql(name, options) click to toggle source

SQLite support creating temporary views.

    # File lib/sequel/adapters/shared/sqlite.rb
337 def create_view_prefix_sql(name, options)
338   create_view_sql_append_columns("CREATE #{'TEMPORARY 'if options[:temp]}VIEW #{quote_schema_table(name)}", options[:columns])
339 end
database_error_regexps() click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
349 def database_error_regexps
350   DATABASE_ERROR_REGEXPS
351 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
354 def database_specific_error_class(exception, opts)
355   case sqlite_error_code(exception)
356   when 1299
357     NotNullConstraintViolation
358   when 1555, 2067, 2579
359     UniqueConstraintViolation
360   when 787
361     ForeignKeyConstraintViolation
362   when 275
363     CheckConstraintViolation
364   when 19
365     ConstraintViolation
366   when 517
367     SerializationFailure
368   else
369     super
370   end
371 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
374 def defined_columns_for(table)
375   cols = parse_pragma(table, OPTS)
376   cols.each do |c|
377     c[:default] = LiteralString.new(c[:default]) if c[:default]
378     c[:type] = c[:db_type]
379   end
380   cols
381 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
386 def duplicate_table(table, opts=OPTS)
387   remove_cached_schema(table)
388   def_columns = defined_columns_for(table)
389   old_columns = def_columns.map{|c| c[:name]}
390   opts[:old_columns_proc].call(old_columns) if opts[:old_columns_proc]
391 
392   yield def_columns if block_given?
393 
394   constraints = (opts[:constraints] || []).dup
395   pks = []
396   def_columns.each{|c| pks << c[:name] if c[:primary_key]}
397   if pks.length > 1
398     constraints << {:type=>:primary_key, :columns=>pks}
399     def_columns.each{|c| c[:primary_key] = false if c[:primary_key]}
400   end
401 
402   # If dropping a foreign key constraint, drop all foreign key constraints,
403   # as there is no way to determine which one to drop.
404   unless opts[:no_foreign_keys]
405     fks = foreign_key_list(table)
406 
407     # If dropping a column, if there is a foreign key with that
408     # column, don't include it when building a copy of the table.
409     if ocp = opts[:old_columns_proc]
410       fks.delete_if{|c| ocp.call(c[:columns].dup) != c[:columns]}
411     end
412     
413     # Skip any foreign key columns where a constraint for those
414     # foreign keys is being dropped.
415     if sfkc = opts[:skip_foreign_key_columns]
416       fks.delete_if{|c| c[:columns] == sfkc}
417     end
418 
419     constraints.concat(fks.each{|h| h[:type] = :foreign_key})
420   end
421 
422   # Determine unique constraints and make sure the new columns have them
423   unique_columns = []
424   skip_indexes = []
425   indexes(table, :only_autocreated=>true).each do |name, h|
426     skip_indexes << name
427     if h[:unique]
428       if h[:columns].length == 1
429         unique_columns.concat(h[:columns])
430       elsif h[:columns].map(&:to_s) != pks && !opts[:no_unique]
431         constraints << {:type=>:unique, :columns=>h[:columns]}
432       end
433     end
434   end
435   unique_columns -= pks
436   unless unique_columns.empty?
437     unique_columns.map!{|c| quote_identifier(c)}
438     def_columns.each do |c|
439       c[:unique] = true if unique_columns.include?(quote_identifier(c[:name])) && c[:unique] != false
440     end
441   end
442   
443   def_columns_str = (def_columns.map{|c| column_definition_sql(c)} + constraints.map{|c| constraint_definition_sql(c)}).join(', ')
444   new_columns = old_columns.dup
445   opts[:new_columns_proc].call(new_columns) if opts[:new_columns_proc]
446 
447   qt = quote_schema_table(table)
448   bt = quote_identifier(backup_table_name(qt))
449   a = [
450      "ALTER TABLE #{qt} RENAME TO #{bt}",
451      "CREATE TABLE #{qt}(#{def_columns_str})",
452      "INSERT INTO #{qt}(#{dataset.send(:identifier_list, new_columns)}) SELECT #{dataset.send(:identifier_list, old_columns)} FROM #{bt}",
453      "DROP TABLE #{bt}"
454   ]
455   indexes(table).each do |name, h|
456     next if skip_indexes.include?(name)
457     if (h[:columns].map(&:to_s) - new_columns).empty?
458       a << alter_table_sql(table, h.merge(:op=>:add_index, :name=>name))
459     end
460   end
461   a
462 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
466 def on_delete_sql_to_sym(str)
467   case str
468   when 'RESTRICT'
469     :restrict
470   when 'CASCADE'
471     :cascade
472   when 'SET NULL'
473     :set_null
474   when 'SET DEFAULT'
475     :set_default
476   when 'NO ACTION'
477     :no_action
478   end
479 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
482 def parse_pragma(table_name, opts)
483   pks = 0
484   sch = _parse_pragma_ds(table_name, opts).map do |row|
485     if sqlite_version > 33100
486       # table_xinfo PRAGMA used, remove hidden columns
487       # that are not generated columns
488       if row[:generated] = (row.delete(:hidden) != 0)
489         next unless row[:type].end_with?(' GENERATED ALWAYS')
490         row[:type] = row[:type].sub(' GENERATED ALWAYS', '')
491       end
492     end
493 
494     row.delete(:cid)
495     row[:allow_null] = row.delete(:notnull).to_i == 0
496     row[:default] = row.delete(:dflt_value)
497     row[:default] = nil if blank_object?(row[:default]) || row[:default] == 'NULL'
498     row[:db_type] = row.delete(:type)
499     if row[:primary_key] = row.delete(:pk).to_i > 0
500       pks += 1
501       # Guess that an integer primary key uses auto increment,
502       # since that is Sequel's default and SQLite does not provide
503       # a way to introspect whether it is actually autoincrementing.
504       row[:auto_increment] = row[:db_type].downcase == 'integer'
505     end
506     row[:type] = schema_column_type(row[:db_type])
507     row
508   end
509 
510   sch.compact!
511 
512   if pks > 1
513     # SQLite does not allow use of auto increment for tables
514     # with composite primary keys, so remove auto_increment
515     # if composite primary keys are detected.
516     sch.each{|r| r.delete(:auto_increment)}
517   end
518 
519   sch
520 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
524 def schema_parse_table(table_name, opts)
525   m = output_identifier_meth(opts[:dataset])
526   parse_pragma(table_name, opts).map do |row|
527     [m.call(row.delete(:name)), row]
528   end
529 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
532 def sqlite_error_code(exception)
533   nil
534 end
tables_and_views(filter, opts) click to toggle source

Backbone of the tables and views support.

    # File lib/sequel/adapters/shared/sqlite.rb
537 def tables_and_views(filter, opts)
538   m = output_identifier_meth
539   metadata_dataset.from(:sqlite_master).server(opts[:server]).where(filter).map{|r| m.call(r[:name])}
540 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
545 def type_literal_generic_bignum_symbol(column)
546   column[:auto_increment] ? :integer : super
547 end