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
PRIMARY_KEY_INDEX_RE
SYNCHRONOUS
TABLES_FILTER
TEMP_STORE
TRANSACTION_MODE
VIEWS_FILTER

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. For backwards compatibility, it is set to true by default. Anyone wanting to use SQLite's datetime functions should set it to false using this method. It's possible that the default will change in a future version, so anyone relying on timezones in timestamps should set this to true.

Public Instance Methods

auto_vacuum() click to toggle source

A symbol signifying the value of the #auto_vacuum PRAGMA.

# File lib/sequel/adapters/shared/sqlite.rb, line 29
def auto_vacuum
  AUTO_VACUUM[pragma_get(:auto_vacuum).to_i]
end
auto_vacuum=(value) click to toggle source

Set the #auto_vacuum PRAGMA using the given symbol (:none, :full, or :incremental). See pragma_set. Consider using the :auto_vacuum Database option instead.

# File lib/sequel/adapters/shared/sqlite.rb, line 36
def auto_vacuum=(value)
  value = AUTO_VACUUM.index(value) || (raise Error, "Invalid value for auto_vacuum option. Please specify one of :none, :full, :incremental.")
  pragma_set(:auto_vacuum, value)
end
case_sensitive_like=(value) click to toggle source

Set the case_sensitive_like PRAGMA using the given boolean value, if using SQLite 3.2.3+. If not using 3.2.3+, no error is raised. See pragma_set. Consider using the :case_sensitive_like Database option instead.

# File lib/sequel/adapters/shared/sqlite.rb, line 44
def case_sensitive_like=(value)
  pragma_set(:case_sensitive_like, !!value ? 'on' : 'off') if sqlite_version >= 30203
end
database_type() click to toggle source

SQLite uses the :sqlite database type.

# File lib/sequel/adapters/shared/sqlite.rb, line 61
def database_type
  :sqlite
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, line 80
def foreign_key_list(table, opts=OPTS)
  m = output_identifier_meth
  h = {}
  metadata_dataset.with_sql("PRAGMA foreign_key_list(?)", input_identifier_meth.call(table)).each do |row|
    if r = h[row[:id]]
      r[:columns] << m.call(row[:from])
      r[:key] << m.call(row[:to]) if r[:key]
    else
      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])}
    end
  end
  h.values
end
foreign_keys() click to toggle source

Boolean signifying the value of the #foreign_keys PRAGMA, or nil if not using SQLite 3.6.19+.

# File lib/sequel/adapters/shared/sqlite.rb, line 67
def foreign_keys
  pragma_get(:foreign_keys).to_i == 1 if sqlite_version >= 30619
end
foreign_keys=(value) click to toggle source

Set the #foreign_keys PRAGMA using the given boolean value, if using SQLite 3.6.19+. If not using 3.6.19+, no error is raised. See pragma_set. Consider using the :foreign_keys Database option instead.

# File lib/sequel/adapters/shared/sqlite.rb, line 74
def foreign_keys=(value)
  pragma_set(:foreign_keys, !!value ? 'on' : 'off') if sqlite_version >= 30619
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, line 95
def indexes(table, opts=OPTS)
  m = output_identifier_meth
  im = input_identifier_meth
  indexes = {}
  metadata_dataset.with_sql("PRAGMA index_list(?)", im.call(table)).each do |r|
    next if r[:name] =~ PRIMARY_KEY_INDEX_RE
    indexes[m.call(r[:name])] = {:unique=>r[:unique].to_i==1}
  end
  indexes.each do |k, v|
    v[:columns] = metadata_dataset.with_sql("PRAGMA index_info(?)", im.call(k)).map(:name).map{|x| m.call(x)}
  end
  indexes
end
pragma_get(name) click to toggle source

Get the value of the given PRAGMA.

# File lib/sequel/adapters/shared/sqlite.rb, line 110
def pragma_get(name)
  self["PRAGMA #{name}"].single_value
end
pragma_set(name, value) click to toggle source

Set the value of the given PRAGMA to value.

This method is not thread safe, and will not work correctly if there are multiple connections in the Database's connection pool. PRAGMA modifications should be done when the connection is created, using an option provided when creating the Database object.

# File lib/sequel/adapters/shared/sqlite.rb, line 120
def pragma_set(name, value)
  execute_ddl("PRAGMA #{name} = #{value}")
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, line 125
def set_integer_booleans
  @integer_booleans = @opts.has_key?(:integer_booleans) ? typecast_value_boolean(@opts[:integer_booleans]) : true
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, line 131
def sqlite_version
  return @sqlite_version if defined?(@sqlite_version)
  @sqlite_version = begin
    v = get{sqlite_version{}}
    [10000, 100, 1].zip(v.split('.')).inject(0){|a, m| a + m[0] * Integer(m[1])}
  rescue
    0
  end
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, line 142
def supports_create_table_if_not_exists?
  sqlite_version >= 30300
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, line 147
def supports_deferrable_foreign_key_constraints?
  sqlite_version >= 30619
end
supports_savepoints?() click to toggle source

SQLite 3.6.8+ supports savepoints.

# File lib/sequel/adapters/shared/sqlite.rb, line 152
def supports_savepoints?
  sqlite_version >= 30608
end
synchronous() click to toggle source

A symbol signifying the value of the synchronous PRAGMA.

# File lib/sequel/adapters/shared/sqlite.rb, line 170
def synchronous
  SYNCHRONOUS[pragma_get(:synchronous).to_i]
end
synchronous=(value) click to toggle source

Set the synchronous PRAGMA using the given symbol (:off, :normal, or :full). See pragma_set. Consider using the :synchronous Database option instead.

# File lib/sequel/adapters/shared/sqlite.rb, line 176
def synchronous=(value)
  value = SYNCHRONOUS.index(value) || (raise Error, "Invalid value for synchronous option. Please specify one of :off, :normal, :full.")
  pragma_set(:synchronous, value)
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, line 185
def tables(opts=OPTS)
  tables_and_views(TABLES_FILTER, opts)
end
temp_store() click to toggle source

A symbol signifying the value of the #temp_store PRAGMA.

# File lib/sequel/adapters/shared/sqlite.rb, line 190
def temp_store
  TEMP_STORE[pragma_get(:temp_store).to_i]
end
temp_store=(value) click to toggle source

Set the #temp_store PRAGMA using the given symbol (:default, :file, or :memory). See pragma_set. Consider using the :temp_store Database option instead.

# File lib/sequel/adapters/shared/sqlite.rb, line 196
def temp_store=(value)
  value = TEMP_STORE.index(value) || (raise Error, "Invalid value for temp_store option. Please specify one of :default, :file, :memory.")
  pragma_set(:temp_store, value)
end
transaction_mode=(value) click to toggle source

Set the default transaction mode.

# File lib/sequel/adapters/shared/sqlite.rb, line 52
def transaction_mode=(value)
  if TRANSACTION_MODE.include?(value)
    @transaction_mode = value
  else
    raise Error, "Invalid value for transaction_mode.  Please specify one of :deferred, :immediate, :exclusive, nil"
  end
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, line 165
def use_timestamp_timezones?
  defined?(@use_timestamp_timezones) ? @use_timestamp_timezones : (@use_timestamp_timezones = false)
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, line 205
def views(opts=OPTS)
  tables_and_views(VIEWS_FILTER, opts)
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, line 235
def alter_table_sql(table, op)
  case op[:op]
  when :add_index, :drop_index
    super
  when :add_column
    if op[:unique] || op[:primary_key]
      duplicate_table(table){|columns| columns.push(op)}
    else
      super
    end
  when :drop_column
    ocp = lambda{|oc| oc.delete_if{|c| c.to_s == op[:name].to_s}}
    duplicate_table(table, :old_columns_proc=>ocp){|columns| columns.delete_if{|s| s[:name].to_s == op[:name].to_s}}
  when :rename_column
    ncp = lambda{|nc| nc.map!{|c| c.to_s == op[:name].to_s ? op[:new_name] : c}}
    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}}
  when :set_column_default
    duplicate_table(table){|columns| columns.each{|s| s[:default] = op[:default] if s[:name].to_s == op[:name].to_s}}
  when :set_column_null
    duplicate_table(table){|columns| columns.each{|s| s[:null] = op[:null] if s[:name].to_s == op[:name].to_s}}
  when :set_column_type
    duplicate_table(table){|columns| columns.each{|s| s.merge!(op) if s[:name].to_s == op[:name].to_s}}
  when :drop_constraint
    case op[:type]
    when :primary_key
      duplicate_table(table){|columns| columns.each{|s| s[:primary_key] = nil}}
    when :foreign_key
      if op[:columns]
        duplicate_table(table, :skip_foreign_key_columns=>op[:columns])
      else
        duplicate_table(table, :no_foreign_keys=>true)
      end
    else
      duplicate_table(table)
    end
  when :add_constraint
    duplicate_table(table, :constraints=>[op])
  when :add_constraints
    duplicate_table(table, :constraints=>op[:ops])
  else
    raise Error, "Unsupported ALTER TABLE operation: #{op[:op].inspect}"
  end
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, line 213
def apply_alter_table(table, ops)
  fks = foreign_keys
  self.foreign_keys = false if fks
  transaction do 
    if ops.length > 1 && ops.all?{|op| op[:op] == :add_constraint}
      # If you are just doing constraints, apply all of them at the same time,
      # as otherwise all but the last one get lost.
      alter_table_sql_list(table, [{:op=>:add_constraints, :ops=>ops}]).flatten.each{|sql| execute_ddl(sql)}
    else
      # Run each operation separately, as later operations may depend on the
      # results of earlier operations.
      ops.each{|op| alter_table_sql_list(table, [op]).flatten.each{|sql| execute_ddl(sql)}}
    end
  end
ensure
  self.foreign_keys = true if fks
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, line 287
def backup_table_name(table, opts=OPTS)
  table = table.gsub('`', '')
  (opts[:times]||1000).times do |i|
    table_name = "#{table}_backup#{i}"
    return table_name unless table_exists?(table_name)
  end
end
begin_new_transaction(conn, opts) click to toggle source
# File lib/sequel/adapters/shared/sqlite.rb, line 279
def begin_new_transaction(conn, opts)
  mode = opts[:mode] || @transaction_mode
  sql = TRANSACTION_MODE[mode] or raise Error, "transaction :mode must be one of: :deferred, :immediate, :exclusive, nil"
  log_connection_execute(conn, sql)
  set_transaction_isolation(conn, opts)
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, line 296
def column_definition_default_sql(sql, column)
  sql << " DEFAULT (#{literal(column[:default])})" if column.include?(:default)
end
column_definition_null_sql(sql, column) click to toggle source

Add null/not null SQL fragment to column creation SQL.

Calls superclass method
# File lib/sequel/adapters/shared/sqlite.rb, line 301
def column_definition_null_sql(sql, column)
  column = column.merge(:null=>false) if column[:primary_key]
  super(sql, column)
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, line 308
def connection_pragmas
  ps = []
  v = typecast_value_boolean(opts.fetch(:foreign_keys, 1))
  ps << "PRAGMA foreign_keys = #{v ? 1 : 0}"
  v = typecast_value_boolean(opts.fetch(:case_sensitive_like, 1))
  ps << "PRAGMA case_sensitive_like = #{v ? 1 : 0}"
  [[:auto_vacuum, AUTO_VACUUM], [:synchronous, SYNCHRONOUS], [:temp_store, TEMP_STORE]].each do |prag, con|
    if v = opts[prag]
      raise(Error, "Value for PRAGMA #{prag} not supported, should be one of #{con.join(', ')}") unless v = con.index(v.to_sym)
      ps << "PRAGMA #{prag} = #{v}"
    end
  end
  ps
end
create_view_prefix_sql(name, options) click to toggle source

SQLite support creating temporary views.

# File lib/sequel/adapters/shared/sqlite.rb, line 324
def create_view_prefix_sql(name, options)
  "CREATE #{'TEMPORARY 'if options[:temp]}VIEW #{quote_schema_table(name)}"
end
database_error_regexps() click to toggle source
# File lib/sequel/adapters/shared/sqlite.rb, line 334
def database_error_regexps
  DATABASE_ERROR_REGEXPS
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, line 339
def defined_columns_for(table)
  cols = parse_pragma(table, {})
  cols.each do |c|
    c[:default] = LiteralString.new(c[:default]) if c[:default]
    c[:type] = c[:db_type]
  end
  cols
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, line 351
def duplicate_table(table, opts=OPTS)
  remove_cached_schema(table)
  def_columns = defined_columns_for(table)
  old_columns = def_columns.map{|c| c[:name]}
  opts[:old_columns_proc].call(old_columns) if opts[:old_columns_proc]

  yield def_columns if block_given?

  constraints = (opts[:constraints] || []).dup
  pks = []
  def_columns.each{|c| pks << c[:name] if c[:primary_key]}
  if pks.length > 1
    constraints << {:type=>:primary_key, :columns=>pks}
    def_columns.each{|c| c[:primary_key] = false if c[:primary_key]}
  end

  # If dropping a foreign key constraint, drop all foreign key constraints,
  # as there is no way to determine which one to drop.
  unless opts[:no_foreign_keys]
    fks = foreign_key_list(table)

    # If dropping a column, if there is a foreign key with that
    # column, don't include it when building a copy of the table.
    if ocp = opts[:old_columns_proc]
      fks.delete_if{|c| ocp.call(c[:columns].dup) != c[:columns]}
    end
    
    # Skip any foreign key columns where a constraint for those
    # foreign keys is being dropped.
    if sfkc = opts[:skip_foreign_key_columns]
      fks.delete_if{|c| c[:columns] == sfkc}
    end

    constraints.concat(fks.each{|h| h[:type] = :foreign_key})
  end

  def_columns_str = (def_columns.map{|c| column_definition_sql(c)} + constraints.map{|c| constraint_definition_sql(c)}).join(', ')
  new_columns = old_columns.dup
  opts[:new_columns_proc].call(new_columns) if opts[:new_columns_proc]

  qt = quote_schema_table(table)
  bt = quote_identifier(backup_table_name(qt))
  a = [
     "ALTER TABLE #{qt} RENAME TO #{bt}",
     "CREATE TABLE #{qt}(#{def_columns_str})",
     "INSERT INTO #{qt}(#{dataset.send(:identifier_list, new_columns)}) SELECT #{dataset.send(:identifier_list, old_columns)} FROM #{bt}",
     "DROP TABLE #{bt}"
  ]
  indexes(table).each do |name, h|
    if (h[:columns].map{|x| x.to_s} - new_columns).empty?
      a << alter_table_sql(table, h.merge(:op=>:add_index, :name=>name))
    end
  end
  a
end
identifier_input_method_default() click to toggle source

SQLite folds unquoted identifiers to lowercase, so it shouldn't need to upcase identifiers on input.

# File lib/sequel/adapters/shared/sqlite.rb, line 408
def identifier_input_method_default
  nil
end
identifier_output_method_default() click to toggle source

SQLite folds unquoted identifiers to lowercase, so it shouldn't need to upcase identifiers on output.

# File lib/sequel/adapters/shared/sqlite.rb, line 413
def identifier_output_method_default
  nil
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, line 419
def on_delete_sql_to_sym str
  case str
  when 'RESTRICT'
    :restrict
  when 'CASCADE'
    :cascade
  when 'SET NULL'
    :set_null
  when 'SET DEFAULT'
    :set_default
  when 'NO ACTION'
    :no_action
  end
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, line 435
def parse_pragma(table_name, opts)
  metadata_dataset.with_sql("PRAGMA table_info(?)", input_identifier_meth(opts[:dataset]).call(table_name)).map do |row|
    row.delete(:cid)
    row[:allow_null] = row.delete(:notnull).to_i == 0
    row[:default] = row.delete(:dflt_value)
    row[:primary_key] = row.delete(:pk).to_i > 0
    row[:default] = nil if blank_object?(row[:default]) || row[:default] == 'NULL'
    row[:db_type] = row.delete(:type)
    row[:type] = schema_column_type(row[:db_type])
    row
  end
end
schema_autoincrementing_primary_key?(schema) click to toggle source

SQLite treats integer primary keys as autoincrementing (alias of rowid).

Calls superclass method
# File lib/sequel/adapters/shared/sqlite.rb, line 449
def schema_autoincrementing_primary_key?(schema)
  super && schema[:db_type].downcase == 'integer'
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, line 455
def schema_parse_table(table_name, opts)
  m = output_identifier_meth(opts[:dataset])
  parse_pragma(table_name, opts).map do |row|
    [m.call(row.delete(:name)), row]
  end
end
tables_and_views(filter, opts) click to toggle source

Backbone of the tables and views support.

# File lib/sequel/adapters/shared/sqlite.rb, line 463
def tables_and_views(filter, opts)
  m = output_identifier_meth
  metadata_dataset.from(:sqlite_master).server(opts[:server]).filter(filter).map{|r| m.call(r[:name])}
end
type_literal_generic_bignum(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, line 471
def type_literal_generic_bignum(column)
  column[:auto_increment] ? :integer : super
end