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

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
53 def database_type
54   :sqlite
55 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
64 def foreign_key_list(table, opts=OPTS)
65   m = output_identifier_meth
66   h = {}
67   _foreign_key_list_ds(table).each do |row|
68     if r = h[row[:id]]
69       r[:columns] << m.call(row[:from])
70       r[:key] << m.call(row[:to]) if r[:key]
71     else
72       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])}
73     end
74   end
75   h.values
76 end
freeze() click to toggle source
Calls superclass method
   # File lib/sequel/adapters/shared/sqlite.rb
78 def freeze
79   sqlite_version
80   use_timestamp_timezones?
81   super
82 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
 85 def indexes(table, opts=OPTS)
 86   m = output_identifier_meth
 87   im = input_identifier_meth
 88   indexes = {}
 89   table = table.value if table.is_a?(Sequel::SQL::Identifier)
 90   metadata_dataset.with_sql("PRAGMA index_list(?)", im.call(table)).each do |r|
 91     if opts[:only_autocreated]
 92       # If specifically asked for only autocreated indexes, then return those an only those
 93       next unless r[:name] =~ /\Asqlite_autoindex_/
 94     elsif r.has_key?(:origin)
 95       # If origin is set, then only exclude primary key indexes and partial indexes
 96       next if r[:origin] == 'pk'
 97       next if r[:partial].to_i == 1
 98     else
 99       # When :origin key not present, assume any autoindex could be a primary key one and exclude it
100       next if r[:name] =~ /\Asqlite_autoindex_/
101     end
102 
103     indexes[m.call(r[:name])] = {:unique=>r[:unique].to_i==1}
104   end
105   indexes.each do |k, v|
106     v[:columns] = metadata_dataset.with_sql("PRAGMA index_info(?)", im.call(k)).map(:name).map{|x| m.call(x)}
107   end
108   indexes
109 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
58 def set_integer_booleans
59   @integer_booleans = @opts.has_key?(:integer_booleans) ? typecast_value_boolean(@opts[:integer_booleans]) : true
60 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
113 def sqlite_version
114   return @sqlite_version if defined?(@sqlite_version)
115   @sqlite_version = begin
116     v = fetch('SELECT sqlite_version()').single_value
117     [10000, 100, 1].zip(v.split('.')).inject(0){|a, m| a + m[0] * Integer(m[1])}
118   rescue
119     0
120   end
121 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
124 def supports_create_table_if_not_exists?
125   sqlite_version >= 30300
126 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
129 def supports_deferrable_foreign_key_constraints?
130   sqlite_version >= 30619
131 end
supports_partial_indexes?() click to toggle source

SQLite 3.8.0+ supports partial indexes.

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

SQLite 3.6.8+ supports savepoints.

    # File lib/sequel/adapters/shared/sqlite.rb
139 def supports_savepoints?
140   sqlite_version >= 30608
141 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
158 def tables(opts=OPTS)
159   tables_and_views(Sequel.~(:name=>'sqlite_sequence') & {:type => 'table'}, opts)
160 end
transaction_mode=(value) click to toggle source

Set the default transaction mode.

   # File lib/sequel/adapters/shared/sqlite.rb
44 def transaction_mode=(value)
45   if TRANSACTION_MODE.include?(value)
46     @transaction_mode = value
47   else
48     raise Error, "Invalid value for transaction_mode.  Please specify one of :deferred, :immediate, :exclusive, nil"
49   end
50 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
150 def use_timestamp_timezones?
151   defined?(@use_timestamp_timezones) ? @use_timestamp_timezones : (@use_timestamp_timezones = false)
152 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
166 def values(v)
167   @default_dataset.clone(:values=>v)
168 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
174 def views(opts=OPTS)
175   tables_and_views({:type => 'view'}, opts)
176 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
181 def _foreign_key_list_ds(table)
182   metadata_dataset.with_sql("PRAGMA foreign_key_list(?)", input_identifier_meth.call(table))
183 end
_parse_pragma_ds(table_name, opts) click to toggle source

Dataset used for parsing schema

    # File lib/sequel/adapters/shared/sqlite.rb
186 def _parse_pragma_ds(table_name, opts)
187   metadata_dataset.with_sql("PRAGMA table_#{'x' if sqlite_version > 33100}info(?)", input_identifier_meth(opts[:dataset]).call(table_name))
188 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
226 def alter_table_sql(table, op)
227   case op[:op]
228   when :add_index, :drop_index
229     super
230   when :add_column
231     if op[:unique] || op[:primary_key]
232       duplicate_table(table){|columns| columns.push(op)}
233     else
234       super
235     end
236   when :drop_column
237     ocp = lambda{|oc| oc.delete_if{|c| c.to_s == op[:name].to_s}}
238     duplicate_table(table, :old_columns_proc=>ocp){|columns| columns.delete_if{|s| s[:name].to_s == op[:name].to_s}}
239   when :rename_column
240     if sqlite_version >= 32500
241       super
242     else
243       ncp = lambda{|nc| nc.map!{|c| c.to_s == op[:name].to_s ? op[:new_name] : c}}
244       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}}
245     end
246   when :set_column_default
247     duplicate_table(table){|columns| columns.each{|s| s[:default] = op[:default] if s[:name].to_s == op[:name].to_s}}
248   when :set_column_null
249     duplicate_table(table){|columns| columns.each{|s| s[:null] = op[:null] if s[:name].to_s == op[:name].to_s}}
250   when :set_column_type
251     duplicate_table(table){|columns| columns.each{|s| s.merge!(op) if s[:name].to_s == op[:name].to_s}}
252   when :drop_constraint
253     case op[:type]
254     when :primary_key
255       duplicate_table(table) do |columns|
256         columns.each do |s|
257           s[:unique] = false if s[:primary_key]
258           s[:primary_key] = s[:auto_increment] = nil
259         end
260       end
261     when :foreign_key
262       if op[:columns]
263         duplicate_table(table, :skip_foreign_key_columns=>op[:columns])
264       else
265         duplicate_table(table, :no_foreign_keys=>true)
266       end
267     else
268       duplicate_table(table)
269     end
270   when :add_constraint
271     duplicate_table(table, :constraints=>[op])
272   when :add_constraints
273     duplicate_table(table, :constraints=>op[:ops])
274   else
275     raise Error, "Unsupported ALTER TABLE operation: #{op[:op].inspect}"
276   end
277 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
192 def apply_alter_table(table, ops)
193   fks = fetch("PRAGMA foreign_keys")
194   if fks
195     run "PRAGMA foreign_keys = 0"
196     run "PRAGMA legacy_alter_table = 1" if sqlite_version >= 32600
197   end
198   transaction do 
199     if ops.length > 1 && ops.all?{|op| op[:op] == :add_constraint || op[:op] == :set_column_null}
200       null_ops, ops = ops.partition{|op| op[:op] == :set_column_null}
201 
202       # Apply NULL/NOT NULL ops first, since those should be purely idependent of the constraints.
203       null_ops.each{|op| alter_table_sql_list(table, [op]).flatten.each{|sql| execute_ddl(sql)}}
204 
205       # If you are just doing constraints, apply all of them at the same time,
206       # as otherwise all but the last one get lost.
207       alter_table_sql_list(table, [{:op=>:add_constraints, :ops=>ops}]).flatten.each{|sql| execute_ddl(sql)}
208     else
209       # Run each operation separately, as later operations may depend on the
210       # results of earlier operations.
211       ops.each{|op| alter_table_sql_list(table, [op]).flatten.each{|sql| execute_ddl(sql)}}
212     end
213   end
214   remove_cached_schema(table)
215 ensure
216   if fks
217     run "PRAGMA foreign_keys = 1"
218     run "PRAGMA legacy_alter_table = 0" if sqlite_version >= 32600
219   end
220 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
287 def backup_table_name(table, opts=OPTS)
288   table = table.gsub('`', '')
289   (opts[:times]||1000).times do |i|
290     table_name = "#{table}_backup#{i}"
291     return table_name unless table_exists?(table_name)
292   end
293 end
begin_new_transaction(conn, opts) click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
279 def begin_new_transaction(conn, opts)
280   mode = opts[:mode] || @transaction_mode
281   sql = TRANSACTION_MODE[mode] or raise Error, "transaction :mode must be one of: :deferred, :immediate, :exclusive, nil"
282   log_connection_execute(conn, sql)
283   set_transaction_isolation(conn, opts)
284 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
297 def can_add_primary_key_constraint_on_nullable_columns?
298   false
299 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
302 def column_definition_default_sql(sql, column)
303   sql << " DEFAULT (#{literal(column[:default])})" if column.include?(:default)
304   if (generated = column[:generated_always_as])
305     if (generated_type = column[:generated_type]) && (generated_type == :stored || generated_type == :virtual)
306       generated_type = generated_type.to_s.upcase
307     end
308     sql << " GENERATED ALWAYS AS (#{literal(generated)}) #{generated_type}"
309   end
310 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
314 def connection_pragmas
315   ps = []
316   v = typecast_value_boolean(opts.fetch(:foreign_keys, 1))
317   ps << "PRAGMA foreign_keys = #{v ? 1 : 0}"
318   v = typecast_value_boolean(opts.fetch(:case_sensitive_like, 1))
319   ps << "PRAGMA case_sensitive_like = #{v ? 1 : 0}"
320   [[:auto_vacuum, AUTO_VACUUM], [:synchronous, SYNCHRONOUS], [:temp_store, TEMP_STORE]].each do |prag, con|
321     if v = opts[prag]
322       raise(Error, "Value for PRAGMA #{prag} not supported, should be one of #{con.join(', ')}") unless v = con.index(v.to_sym)
323       ps << "PRAGMA #{prag} = #{v}"
324     end
325   end
326   ps
327 end
create_view_prefix_sql(name, options) click to toggle source

SQLite support creating temporary views.

    # File lib/sequel/adapters/shared/sqlite.rb
330 def create_view_prefix_sql(name, options)
331   create_view_sql_append_columns("CREATE #{'TEMPORARY 'if options[:temp]}VIEW #{quote_schema_table(name)}", options[:columns])
332 end
database_error_regexps() click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
342 def database_error_regexps
343   DATABASE_ERROR_REGEXPS
344 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
347 def database_specific_error_class(exception, opts)
348   case sqlite_error_code(exception)
349   when 1299
350     NotNullConstraintViolation
351   when 1555, 2067, 2579
352     UniqueConstraintViolation
353   when 787
354     ForeignKeyConstraintViolation
355   when 275
356     CheckConstraintViolation
357   when 19
358     ConstraintViolation
359   when 517
360     SerializationFailure
361   else
362     super
363   end
364 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
367 def defined_columns_for(table)
368   cols = parse_pragma(table, OPTS)
369   cols.each do |c|
370     c[:default] = LiteralString.new(c[:default]) if c[:default]
371     c[:type] = c[:db_type]
372   end
373   cols
374 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
379 def duplicate_table(table, opts=OPTS)
380   remove_cached_schema(table)
381   def_columns = defined_columns_for(table)
382   old_columns = def_columns.map{|c| c[:name]}
383   opts[:old_columns_proc].call(old_columns) if opts[:old_columns_proc]
384 
385   yield def_columns if block_given?
386 
387   constraints = (opts[:constraints] || []).dup
388   pks = []
389   def_columns.each{|c| pks << c[:name] if c[:primary_key]}
390   if pks.length > 1
391     constraints << {:type=>:primary_key, :columns=>pks}
392     def_columns.each{|c| c[:primary_key] = false if c[:primary_key]}
393   end
394 
395   # If dropping a foreign key constraint, drop all foreign key constraints,
396   # as there is no way to determine which one to drop.
397   unless opts[:no_foreign_keys]
398     fks = foreign_key_list(table)
399 
400     # If dropping a column, if there is a foreign key with that
401     # column, don't include it when building a copy of the table.
402     if ocp = opts[:old_columns_proc]
403       fks.delete_if{|c| ocp.call(c[:columns].dup) != c[:columns]}
404     end
405     
406     # Skip any foreign key columns where a constraint for those
407     # foreign keys is being dropped.
408     if sfkc = opts[:skip_foreign_key_columns]
409       fks.delete_if{|c| c[:columns] == sfkc}
410     end
411 
412     constraints.concat(fks.each{|h| h[:type] = :foreign_key})
413   end
414 
415   # Determine unique constraints and make sure the new columns have them
416   unique_columns = []
417   skip_indexes = []
418   indexes(table, :only_autocreated=>true).each do |name, h|
419     skip_indexes << name
420     if h[:columns].length == 1 && h[:unique]
421       unique_columns.concat(h[:columns])
422     end
423   end
424   unique_columns -= pks
425   unless unique_columns.empty?
426     unique_columns.map!{|c| quote_identifier(c)}
427     def_columns.each do |c|
428       c[:unique] = true if unique_columns.include?(quote_identifier(c[:name])) && c[:unique] != false
429     end
430   end
431   
432   def_columns_str = (def_columns.map{|c| column_definition_sql(c)} + constraints.map{|c| constraint_definition_sql(c)}).join(', ')
433   new_columns = old_columns.dup
434   opts[:new_columns_proc].call(new_columns) if opts[:new_columns_proc]
435 
436   qt = quote_schema_table(table)
437   bt = quote_identifier(backup_table_name(qt))
438   a = [
439      "ALTER TABLE #{qt} RENAME TO #{bt}",
440      "CREATE TABLE #{qt}(#{def_columns_str})",
441      "INSERT INTO #{qt}(#{dataset.send(:identifier_list, new_columns)}) SELECT #{dataset.send(:identifier_list, old_columns)} FROM #{bt}",
442      "DROP TABLE #{bt}"
443   ]
444   indexes(table).each do |name, h|
445     next if skip_indexes.include?(name)
446     if (h[:columns].map(&:to_s) - new_columns).empty?
447       a << alter_table_sql(table, h.merge(:op=>:add_index, :name=>name))
448     end
449   end
450   a
451 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
455 def on_delete_sql_to_sym(str)
456   case str
457   when 'RESTRICT'
458     :restrict
459   when 'CASCADE'
460     :cascade
461   when 'SET NULL'
462     :set_null
463   when 'SET DEFAULT'
464     :set_default
465   when 'NO ACTION'
466     :no_action
467   end
468 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
471 def parse_pragma(table_name, opts)
472   pks = 0
473   sch = _parse_pragma_ds(table_name, opts).map do |row|
474     if sqlite_version > 33100
475       # table_xinfo PRAGMA used, remove hidden columns
476       # that are not generated columns
477       if row[:generated] = (row.delete(:hidden) != 0)
478         next unless row[:type].end_with?(' GENERATED ALWAYS')
479         row[:type] = row[:type].sub(' GENERATED ALWAYS', '')
480       end
481     end
482 
483     row.delete(:cid)
484     row[:allow_null] = row.delete(:notnull).to_i == 0
485     row[:default] = row.delete(:dflt_value)
486     row[:default] = nil if blank_object?(row[:default]) || row[:default] == 'NULL'
487     row[:db_type] = row.delete(:type)
488     if row[:primary_key] = row.delete(:pk).to_i > 0
489       pks += 1
490       # Guess that an integer primary key uses auto increment,
491       # since that is Sequel's default and SQLite does not provide
492       # a way to introspect whether it is actually autoincrementing.
493       row[:auto_increment] = row[:db_type].downcase == 'integer'
494     end
495     row[:type] = schema_column_type(row[:db_type])
496     row
497   end
498 
499   sch.compact!
500 
501   if pks > 1
502     # SQLite does not allow use of auto increment for tables
503     # with composite primary keys, so remove auto_increment
504     # if composite primary keys are detected.
505     sch.each{|r| r.delete(:auto_increment)}
506   end
507 
508   sch
509 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
513 def schema_parse_table(table_name, opts)
514   m = output_identifier_meth(opts[:dataset])
515   parse_pragma(table_name, opts).map do |row|
516     [m.call(row.delete(:name)), row]
517   end
518 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
521 def sqlite_error_code(exception)
522   nil
523 end
tables_and_views(filter, opts) click to toggle source

Backbone of the tables and views support.

    # File lib/sequel/adapters/shared/sqlite.rb
526 def tables_and_views(filter, opts)
527   m = output_identifier_meth
528   metadata_dataset.from(:sqlite_master).server(opts[:server]).where(filter).map{|r| m.call(r[:name])}
529 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
534 def type_literal_generic_bignum_symbol(column)
535   column[:auto_increment] ? :integer : super
536 end