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
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
325 def connection_pragmas
326   ps = []
327   v = typecast_value_boolean(opts.fetch(:foreign_keys, 1))
328   ps << "PRAGMA foreign_keys = #{v ? 1 : 0}"
329   v = typecast_value_boolean(opts.fetch(:case_sensitive_like, 1))
330   ps << "PRAGMA case_sensitive_like = #{v ? 1 : 0}"
331   [[:auto_vacuum, AUTO_VACUUM], [:synchronous, SYNCHRONOUS], [:temp_store, TEMP_STORE]].each do |prag, con|
332     if v = opts[prag]
333       raise(Error, "Value for PRAGMA #{prag} not supported, should be one of #{con.join(', ')}") unless v = con.index(v.to_sym)
334       ps << "PRAGMA #{prag} = #{v}"
335     end
336   end
337   ps
338 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
341 def create_table_sql(name, generator, options)
342   "#{super}#{' STRICT' if options[:strict]}"
343 end
create_view_prefix_sql(name, options) click to toggle source

SQLite support creating temporary views.

    # File lib/sequel/adapters/shared/sqlite.rb
346 def create_view_prefix_sql(name, options)
347   create_view_sql_append_columns("CREATE #{'TEMPORARY 'if options[:temp]}VIEW #{quote_schema_table(name)}", options[:columns])
348 end
database_error_regexps() click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
359 def database_error_regexps
360   DATABASE_ERROR_REGEXPS
361 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
364 def database_specific_error_class(exception, opts)
365   case sqlite_error_code(exception)
366   when 1299
367     NotNullConstraintViolation
368   when 1555, 2067, 2579
369     UniqueConstraintViolation
370   when 787
371     ForeignKeyConstraintViolation
372   when 275
373     CheckConstraintViolation
374   when 19
375     ConstraintViolation
376   when 517
377     SerializationFailure
378   else
379     super
380   end
381 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
384 def defined_columns_for(table)
385   cols = parse_pragma(table, OPTS)
386   cols.each do |c|
387     c[:default] = LiteralString.new(c[:default]) if c[:default]
388     c[:type] = c[:db_type]
389   end
390   cols
391 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
396 def duplicate_table(table, opts=OPTS)
397   remove_cached_schema(table)
398   def_columns = defined_columns_for(table)
399   old_columns = def_columns.map{|c| c[:name]}
400   opts[:old_columns_proc].call(old_columns) if opts[:old_columns_proc]
401 
402   yield def_columns if defined?(yield)
403 
404   constraints = (opts[:constraints] || []).dup
405   pks = []
406   def_columns.each{|c| pks << c[:name] if c[:primary_key]}
407   if pks.length > 1
408     constraints << {:type=>:primary_key, :columns=>pks}
409     def_columns.each{|c| c[:primary_key] = false if c[:primary_key]}
410   end
411 
412   # If dropping a foreign key constraint, drop all foreign key constraints,
413   # as there is no way to determine which one to drop.
414   unless opts[:no_foreign_keys]
415     fks = foreign_key_list(table)
416 
417     # If dropping a column, if there is a foreign key with that
418     # column, don't include it when building a copy of the table.
419     if ocp = opts[:old_columns_proc]
420       fks.delete_if{|c| ocp.call(c[:columns].dup) != c[:columns]}
421     end
422     
423     # Skip any foreign key columns where a constraint for those
424     # foreign keys is being dropped.
425     if sfkc = opts[:skip_foreign_key_columns]
426       fks.delete_if{|c| c[:columns] == sfkc}
427     end
428 
429     constraints.concat(fks.each{|h| h[:type] = :foreign_key})
430   end
431 
432   # Determine unique constraints and make sure the new columns have them
433   unique_columns = []
434   skip_indexes = []
435   indexes(table, :only_autocreated=>true).each do |name, h|
436     skip_indexes << name
437     if h[:unique] && !opts[:no_unique]
438       if h[:columns].length == 1
439         unique_columns.concat(h[:columns])
440       elsif h[:columns].map(&:to_s) != pks
441         constraints << {:type=>:unique, :columns=>h[:columns]}
442       end
443     end
444   end
445   unique_columns -= pks
446   unless unique_columns.empty?
447     unique_columns.map!{|c| quote_identifier(c)}
448     def_columns.each do |c|
449       c[:unique] = true if unique_columns.include?(quote_identifier(c[:name])) && c[:unique] != false
450     end
451   end
452   
453   def_columns_str = (def_columns.map{|c| column_definition_sql(c)} + constraints.map{|c| constraint_definition_sql(c)}).join(', ')
454   new_columns = old_columns.dup
455   opts[:new_columns_proc].call(new_columns) if opts[:new_columns_proc]
456 
457   qt = quote_schema_table(table)
458   bt = quote_identifier(backup_table_name(qt))
459   a = [
460      "ALTER TABLE #{qt} RENAME TO #{bt}",
461      "CREATE TABLE #{qt}(#{def_columns_str})",
462      "INSERT INTO #{qt}(#{dataset.send(:identifier_list, new_columns)}) SELECT #{dataset.send(:identifier_list, old_columns)} FROM #{bt}",
463      "DROP TABLE #{bt}"
464   ]
465   indexes(table).each do |name, h|
466     next if skip_indexes.include?(name)
467     if (h[:columns].map(&:to_s) - new_columns).empty?
468       a << alter_table_sql(table, h.merge(:op=>:add_index, :name=>name))
469     end
470   end
471   a
472 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
476 def on_delete_sql_to_sym(str)
477   case str
478   when 'RESTRICT'
479     :restrict
480   when 'CASCADE'
481     :cascade
482   when 'SET NULL'
483     :set_null
484   when 'SET DEFAULT'
485     :set_default
486   when 'NO ACTION'
487     :no_action
488   end
489 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
492 def parse_pragma(table_name, opts)
493   pks = 0
494   sch = _parse_pragma_ds(table_name, opts).map do |row|
495     if sqlite_version > 33100
496       # table_xinfo PRAGMA used, remove hidden columns
497       # that are not generated columns
498       if row[:generated] = (row.delete(:hidden) != 0)
499         next unless row[:type].end_with?(' GENERATED ALWAYS')
500         row[:type] = row[:type].sub(' GENERATED ALWAYS', '')
501       end
502     end
503 
504     row.delete(:cid)
505     row[:allow_null] = row.delete(:notnull).to_i == 0
506     row[:default] = row.delete(:dflt_value)
507     row[:default] = nil if blank_object?(row[:default]) || row[:default] == 'NULL'
508     row[:db_type] = row.delete(:type)
509     if row[:primary_key] = row.delete(:pk).to_i > 0
510       pks += 1
511       # Guess that an integer primary key uses auto increment,
512       # since that is Sequel's default and SQLite does not provide
513       # a way to introspect whether it is actually autoincrementing.
514       row[:auto_increment] = row[:db_type].downcase == 'integer'
515     end
516     row[:type] = schema_column_type(row[:db_type])
517     row
518   end
519 
520   sch.compact!
521 
522   if pks > 1
523     # SQLite does not allow use of auto increment for tables
524     # with composite primary keys, so remove auto_increment
525     # if composite primary keys are detected.
526     sch.each{|r| r.delete(:auto_increment)}
527   end
528 
529   sch
530 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
534 def schema_parse_table(table_name, opts)
535   m = output_identifier_meth(opts[:dataset])
536   parse_pragma(table_name, opts).map do |row|
537     [m.call(row.delete(:name)), row]
538   end
539 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
542 def sqlite_error_code(exception)
543   nil
544 end
tables_and_views(filter, opts) click to toggle source

Backbone of the tables and views support.

    # File lib/sequel/adapters/shared/sqlite.rb
547 def tables_and_views(filter, opts)
548   m = output_identifier_meth
549   metadata_dataset.from(:sqlite_master).server(opts[:server]).where(filter).map{|r| m.call(r[:name])}
550 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
555 def type_literal_generic_bignum_symbol(column)
556   column[:auto_increment] ? :integer : super
557 end