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
49 def database_type
50   :sqlite
51 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
60 def foreign_key_list(table, opts=OPTS)
61   m = output_identifier_meth
62   h = {}
63   metadata_dataset.with_sql("PRAGMA foreign_key_list(?)", input_identifier_meth.call(table)).each do |row|
64     if r = h[row[:id]]
65       r[:columns] << m.call(row[:from])
66       r[:key] << m.call(row[:to]) if r[:key]
67     else
68       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])}
69     end
70   end
71   h.values
72 end
freeze() click to toggle source
Calls superclass method
   # File lib/sequel/adapters/shared/sqlite.rb
74 def freeze
75   sqlite_version
76   use_timestamp_timezones?
77   super
78 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
 81 def indexes(table, opts=OPTS)
 82   m = output_identifier_meth
 83   im = input_identifier_meth
 84   indexes = {}
 85   table = table.value if table.is_a?(Sequel::SQL::Identifier)
 86   metadata_dataset.with_sql("PRAGMA index_list(?)", im.call(table)).each do |r|
 87     if opts[:only_autocreated]
 88       # If specifically asked for only autocreated indexes, then return those an only those
 89       next unless r[:name] =~ /\Asqlite_autoindex_/
 90     elsif r.has_key?(:origin)
 91       # If origin is set, then only exclude primary key indexes and partial indexes
 92       next if r[:origin] == 'pk'
 93       next if r[:partial].to_i == 1
 94     else
 95       # When :origin key not present, assume any autoindex could be a primary key one and exclude it
 96       next if r[:name] =~ /\Asqlite_autoindex_/
 97     end
 98 
 99     indexes[m.call(r[:name])] = {:unique=>r[:unique].to_i==1}
100   end
101   indexes.each do |k, v|
102     v[:columns] = metadata_dataset.with_sql("PRAGMA index_info(?)", im.call(k)).map(:name).map{|x| m.call(x)}
103   end
104   indexes
105 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
54 def set_integer_booleans
55   @integer_booleans = @opts.has_key?(:integer_booleans) ? typecast_value_boolean(@opts[:integer_booleans]) : true
56 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
109 def sqlite_version
110   return @sqlite_version if defined?(@sqlite_version)
111   @sqlite_version = begin
112     v = fetch('SELECT sqlite_version()').single_value
113     [10000, 100, 1].zip(v.split('.')).inject(0){|a, m| a + m[0] * Integer(m[1])}
114   rescue
115     0
116   end
117 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
120 def supports_create_table_if_not_exists?
121   sqlite_version >= 30300
122 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
125 def supports_deferrable_foreign_key_constraints?
126   sqlite_version >= 30619
127 end
supports_partial_indexes?() click to toggle source

SQLite 3.8.0+ supports partial indexes.

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

SQLite 3.6.8+ supports savepoints.

    # File lib/sequel/adapters/shared/sqlite.rb
135 def supports_savepoints?
136   sqlite_version >= 30608
137 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
154 def tables(opts=OPTS)
155   tables_and_views(Sequel.~(:name=>'sqlite_sequence') & {:type => 'table'}, opts)
156 end
transaction_mode=(value) click to toggle source

Set the default transaction mode.

   # File lib/sequel/adapters/shared/sqlite.rb
40 def transaction_mode=(value)
41   if TRANSACTION_MODE.include?(value)
42     @transaction_mode = value
43   else
44     raise Error, "Invalid value for transaction_mode.  Please specify one of :deferred, :immediate, :exclusive, nil"
45   end
46 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
146 def use_timestamp_timezones?
147   defined?(@use_timestamp_timezones) ? @use_timestamp_timezones : (@use_timestamp_timezones = false)
148 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
162 def values(v)
163   @default_dataset.clone(:values=>v)
164 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
170 def views(opts=OPTS)
171   tables_and_views({:type => 'view'}, opts)
172 end

Private Instance Methods

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
206 def alter_table_sql(table, op)
207   case op[:op]
208   when :add_index, :drop_index
209     super
210   when :add_column
211     if op[:unique] || op[:primary_key]
212       duplicate_table(table){|columns| columns.push(op)}
213     else
214       super
215     end
216   when :drop_column
217     ocp = lambda{|oc| oc.delete_if{|c| c.to_s == op[:name].to_s}}
218     duplicate_table(table, :old_columns_proc=>ocp){|columns| columns.delete_if{|s| s[:name].to_s == op[:name].to_s}}
219   when :rename_column
220     ncp = lambda{|nc| nc.map!{|c| c.to_s == op[:name].to_s ? op[:new_name] : c}}
221     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}}
222   when :set_column_default
223     duplicate_table(table){|columns| columns.each{|s| s[:default] = op[:default] if s[:name].to_s == op[:name].to_s}}
224   when :set_column_null
225     duplicate_table(table){|columns| columns.each{|s| s[:null] = op[:null] if s[:name].to_s == op[:name].to_s}}
226   when :set_column_type
227     duplicate_table(table){|columns| columns.each{|s| s.merge!(op) if s[:name].to_s == op[:name].to_s}}
228   when :drop_constraint
229     case op[:type]
230     when :primary_key
231       duplicate_table(table){|columns| columns.each{|s| s[:primary_key] = s[:auto_increment] = nil}}
232     when :foreign_key
233       if op[:columns]
234         duplicate_table(table, :skip_foreign_key_columns=>op[:columns])
235       else
236         duplicate_table(table, :no_foreign_keys=>true)
237       end
238     else
239       duplicate_table(table)
240     end
241   when :add_constraint
242     duplicate_table(table, :constraints=>[op])
243   when :add_constraints
244     duplicate_table(table, :constraints=>op[:ops])
245   else
246     raise Error, "Unsupported ALTER TABLE operation: #{op[:op].inspect}"
247   end
248 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
178 def apply_alter_table(table, ops)
179   fks = fetch("PRAGMA foreign_keys")
180   run "PRAGMA foreign_keys = 0" if fks
181   transaction do 
182     if ops.length > 1 && ops.all?{|op| op[:op] == :add_constraint || op[:op] == :set_column_null}
183       null_ops, ops = ops.partition{|op| op[:op] == :set_column_null}
184 
185       # Apply NULL/NOT NULL ops first, since those should be purely idependent of the constraints.
186       null_ops.each{|op| alter_table_sql_list(table, [op]).flatten.each{|sql| execute_ddl(sql)}}
187 
188       # If you are just doing constraints, apply all of them at the same time,
189       # as otherwise all but the last one get lost.
190       alter_table_sql_list(table, [{:op=>:add_constraints, :ops=>ops}]).flatten.each{|sql| execute_ddl(sql)}
191     else
192       # Run each operation separately, as later operations may depend on the
193       # results of earlier operations.
194       ops.each{|op| alter_table_sql_list(table, [op]).flatten.each{|sql| execute_ddl(sql)}}
195     end
196   end
197   remove_cached_schema(table)
198 ensure
199   run "PRAGMA foreign_keys = 1" if fks
200 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
258 def backup_table_name(table, opts=OPTS)
259   table = table.gsub('`', '')
260   (opts[:times]||1000).times do |i|
261     table_name = "#{table}_backup#{i}"
262     return table_name unless table_exists?(table_name)
263   end
264 end
begin_new_transaction(conn, opts) click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
250 def begin_new_transaction(conn, opts)
251   mode = opts[:mode] || @transaction_mode
252   sql = TRANSACTION_MODE[mode] or raise Error, "transaction :mode must be one of: :deferred, :immediate, :exclusive, nil"
253   log_connection_execute(conn, sql)
254   set_transaction_isolation(conn, opts)
255 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
268 def can_add_primary_key_constraint_on_nullable_columns?
269   false
270 end
column_definition_default_sql(sql, column) click to toggle source

Surround default with parens to appease SQLite

    # File lib/sequel/adapters/shared/sqlite.rb
273 def column_definition_default_sql(sql, column)
274   sql << " DEFAULT (#{literal(column[:default])})" if column.include?(:default)
275 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
279 def connection_pragmas
280   ps = []
281   v = typecast_value_boolean(opts.fetch(:foreign_keys, 1))
282   ps << "PRAGMA foreign_keys = #{v ? 1 : 0}"
283   v = typecast_value_boolean(opts.fetch(:case_sensitive_like, 1))
284   ps << "PRAGMA case_sensitive_like = #{v ? 1 : 0}"
285   [[:auto_vacuum, AUTO_VACUUM], [:synchronous, SYNCHRONOUS], [:temp_store, TEMP_STORE]].each do |prag, con|
286     if v = opts[prag]
287       raise(Error, "Value for PRAGMA #{prag} not supported, should be one of #{con.join(', ')}") unless v = con.index(v.to_sym)
288       ps << "PRAGMA #{prag} = #{v}"
289     end
290   end
291   ps
292 end
create_view_prefix_sql(name, options) click to toggle source

SQLite support creating temporary views.

    # File lib/sequel/adapters/shared/sqlite.rb
295 def create_view_prefix_sql(name, options)
296   create_view_sql_append_columns("CREATE #{'TEMPORARY 'if options[:temp]}VIEW #{quote_schema_table(name)}", options[:columns])
297 end
database_error_regexps() click to toggle source
    # File lib/sequel/adapters/shared/sqlite.rb
307 def database_error_regexps
308   DATABASE_ERROR_REGEXPS
309 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
312 def database_specific_error_class(exception, opts)
313   case sqlite_error_code(exception)
314   when 1299
315     NotNullConstraintViolation
316   when 2067
317     UniqueConstraintViolation
318   when 787
319     ForeignKeyConstraintViolation
320   when 275
321     CheckConstraintViolation
322   when 19
323     ConstraintViolation
324   else
325     super
326   end
327 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
330 def defined_columns_for(table)
331   cols = parse_pragma(table, OPTS)
332   cols.each do |c|
333     c[:default] = LiteralString.new(c[:default]) if c[:default]
334     c[:type] = c[:db_type]
335   end
336   cols
337 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
342 def duplicate_table(table, opts=OPTS)
343   remove_cached_schema(table)
344   def_columns = defined_columns_for(table)
345   old_columns = def_columns.map{|c| c[:name]}
346   opts[:old_columns_proc].call(old_columns) if opts[:old_columns_proc]
347 
348   yield def_columns if block_given?
349 
350   constraints = (opts[:constraints] || []).dup
351   pks = []
352   def_columns.each{|c| pks << c[:name] if c[:primary_key]}
353   if pks.length > 1
354     constraints << {:type=>:primary_key, :columns=>pks}
355     def_columns.each{|c| c[:primary_key] = false if c[:primary_key]}
356   end
357 
358   # If dropping a foreign key constraint, drop all foreign key constraints,
359   # as there is no way to determine which one to drop.
360   unless opts[:no_foreign_keys]
361     fks = foreign_key_list(table)
362 
363     # If dropping a column, if there is a foreign key with that
364     # column, don't include it when building a copy of the table.
365     if ocp = opts[:old_columns_proc]
366       fks.delete_if{|c| ocp.call(c[:columns].dup) != c[:columns]}
367     end
368     
369     # Skip any foreign key columns where a constraint for those
370     # foreign keys is being dropped.
371     if sfkc = opts[:skip_foreign_key_columns]
372       fks.delete_if{|c| c[:columns] == sfkc}
373     end
374 
375     constraints.concat(fks.each{|h| h[:type] = :foreign_key})
376   end
377 
378   # Determine unique constraints and make sure the new columns have them
379   unique_columns = []
380   skip_indexes = []
381   indexes(table, :only_autocreated=>true).each do |name, h|
382     skip_indexes << name
383     if h[:columns].length == 1 && h[:unique]
384       unique_columns.concat(h[:columns])
385     end
386   end
387   unique_columns -= pks
388   unless unique_columns.empty?
389     unique_columns.map!{|c| quote_identifier(c)}
390     def_columns.each do |c|
391       c[:unique] = true if unique_columns.include?(quote_identifier(c[:name]))
392     end
393   end
394   
395   def_columns_str = (def_columns.map{|c| column_definition_sql(c)} + constraints.map{|c| constraint_definition_sql(c)}).join(', ')
396   new_columns = old_columns.dup
397   opts[:new_columns_proc].call(new_columns) if opts[:new_columns_proc]
398 
399   qt = quote_schema_table(table)
400   bt = quote_identifier(backup_table_name(qt))
401   a = [
402      "ALTER TABLE #{qt} RENAME TO #{bt}",
403      "CREATE TABLE #{qt}(#{def_columns_str})",
404      "INSERT INTO #{qt}(#{dataset.send(:identifier_list, new_columns)}) SELECT #{dataset.send(:identifier_list, old_columns)} FROM #{bt}",
405      "DROP TABLE #{bt}"
406   ]
407   indexes(table).each do |name, h|
408     next if skip_indexes.include?(name)
409     if (h[:columns].map(&:to_s) - new_columns).empty?
410       a << alter_table_sql(table, h.merge(:op=>:add_index, :name=>name))
411     end
412   end
413   a
414 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
418 def on_delete_sql_to_sym(str)
419   case str
420   when 'RESTRICT'
421     :restrict
422   when 'CASCADE'
423     :cascade
424   when 'SET NULL'
425     :set_null
426   when 'SET DEFAULT'
427     :set_default
428   when 'NO ACTION'
429     :no_action
430   end
431 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
434 def parse_pragma(table_name, opts)
435   pks = 0
436   sch = metadata_dataset.with_sql("PRAGMA table_info(?)", input_identifier_meth(opts[:dataset]).call(table_name)).map do |row|
437     row.delete(:cid)
438     row[:allow_null] = row.delete(:notnull).to_i == 0
439     row[:default] = row.delete(:dflt_value)
440     row[:default] = nil if blank_object?(row[:default]) || row[:default] == 'NULL'
441     row[:db_type] = row.delete(:type)
442     if row[:primary_key] = row.delete(:pk).to_i > 0
443       pks += 1
444       # Guess that an integer primary key uses auto increment,
445       # since that is Sequel's default and SQLite does not provide
446       # a way to introspect whether it is actually autoincrementing.
447       row[:auto_increment] = row[:db_type].downcase == 'integer'
448     end
449     row[:type] = schema_column_type(row[:db_type])
450     row
451   end
452 
453   if pks > 1
454     # SQLite does not allow use of auto increment for tables
455     # with composite primary keys, so remove auto_increment
456     # if composite primary keys are detected.
457     sch.each{|r| r.delete(:auto_increment)}
458   end
459 
460   sch
461 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
465 def schema_parse_table(table_name, opts)
466   m = output_identifier_meth(opts[:dataset])
467   parse_pragma(table_name, opts).map do |row|
468     [m.call(row.delete(:name)), row]
469   end
470 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
473 def sqlite_error_code(exception)
474   nil
475 end
tables_and_views(filter, opts) click to toggle source

Backbone of the tables and views support.

    # File lib/sequel/adapters/shared/sqlite.rb
478 def tables_and_views(filter, opts)
479   m = output_identifier_meth
480   metadata_dataset.from(:sqlite_master).server(opts[:server]).where(filter).map{|r| m.call(r[:name])}
481 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
486 def type_literal_generic_bignum_symbol(column)
487   column[:auto_increment] ? :integer : super
488 end