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Class: ActiveRecord::ConnectionAdapters::SQLite3Adapter

Relationships & Source Files
Namespace Children
Classes:
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
Instance Chain:
Inherits: ActiveRecord::ConnectionAdapters::AbstractAdapter
Defined in: activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb

Overview

The SQLite3 adapter works SQLite 3.6.16 or newer with the sqlite3-ruby drivers (available as gem from rubygems.org/gems/sqlite3).

Options:

  • :database - Path to the database file.

Constant Summary

::ActiveSupport::Callbacks - Included

CALLBACK_FILTER_TYPES

AbstractAdapter - Inherited

ADAPTER_NAME, SIMPLE_INT

Class Method Summary

AbstractAdapter - Inherited

::ActiveSupport::DescendantsTracker - Inherited

clear, descendants, direct_descendants,
store_inherited

This is the only method that is not thread safe, but is only ever called during the eager loading phase.

Instance Attribute Summary

AbstractAdapter - Inherited

#active?

Checks whether the connection to the database is still active.

#in_use?
#logger, #owner, #pool, #prepared_statements,
#requires_reloading?

Returns true if its required to reload the connection between requests for development mode.

#schema_cache, #schema_cache=, #supports_bulk_alter?,
#supports_ddl_transactions?

Does this adapter support DDL rollbacks in transactions? That is, would CREATE TABLE or ALTER TABLE get rolled back by a transaction?

#supports_explain?

Does this adapter support explain?

#supports_extensions?

Does this adapter support database extensions?

#supports_foreign_keys?

Does this adapter support creating foreign key constraints?

#supports_index_sort_order?

Does this adapter support index sort order?

#supports_indexes_in_create?

Does this adapter support creating indexes in the same statement as creating the table?

#supports_migrations?

Does this adapter support migrations?

#supports_partial_index?

Does this adapter support partial indices?

#supports_primary_key?

Can this adapter determine the primary key for tables not attached to an Active Record class, such as join tables?

#supports_savepoints?

Does this adapter support savepoints?

#supports_transaction_isolation?

Does this adapter support setting the isolation level for a transaction?

#supports_views?

Does this adapter support views?

#visitor

DatabaseStatements - Included

#begin_transaction, #commit_transaction, #current_transaction, #open_transactions, #rollback_transaction,
#supports_statement_cache?

Returns true when the connection adapter supports prepared statement caching, otherwise returns false

#transaction_open?, #within_new_transaction

Instance Method Summary

AbstractAdapter - Inherited

#adapter_name

Returns the human-readable name of the adapter.

#case_insensitive_comparison, #case_sensitive_comparison, #case_sensitive_modifier,
#clear_cache!

Clear any caching the database adapter may be doing, for example clearing the prepared statement cache.

#close

Check the connection back in to the connection pool.

#collector, #create_savepoint, #current_savepoint_name,
#disable_extension

This is meant to be implemented by the adapters that support extensions.

#disable_referential_integrity

Override to turn off referential integrity while executing &block.

#disconnect!

Disconnects from the database if already connected.

#enable_extension

This is meant to be implemented by the adapters that support extensions.

#expire,
#extensions

A list of extensions, to be filled in by adapters that support them.

#index_algorithms

A list of index algorithms, to be filled by adapters that support them.

#lease, #new_column,
#prefetch_primary_key?

Should primary key values be selected from their corresponding sequence before the insert statement? If true, next_sequence_value is called before each insert to set the record's primary key.

#raw_connection

Provides access to the underlying database driver for this adapter.

#reconnect!

Disconnects from the database if already connected, and establishes a new connection with the database.

#release_savepoint,
#reset!

Reset the state of this connection, directing the DBMS to clear transactions and other connection-related server-side state.

#schema_creation,
#substitute_at

Returns a bind substitution value given a bind column NOTE: The column param is currently being used by the sqlserver-adapter.

#unprepared_statement, #valid_type?,
#verify!

Checks whether the connection to the database is still active (i.e. not stale).

ColumnDumper - Included

#column_spec,
#migration_keys

Lists the valid migration options.

#prepare_column_options

This can be overridden on a Adapter level basis to support other extended datatypes (Example: Adding an array option in the PostgreSQLAdapter).

::ActiveSupport::Callbacks - Included

#run_callbacks

Runs the callbacks for the given event.

::ActiveRecord::QueryCache - Included

DatabaseLimits - Included

#allowed_index_name_length

Returns the maximum allowed length for an index name.

#column_name_length

Returns the maximum length of a column name.

#columns_per_multicolumn_index

Returns the maximum number of columns in a multicolumn index.

#columns_per_table

Returns the maximum number of columns per table.

#in_clause_length

Returns the maximum number of elements in an IN (x,y,z) clause.

#index_name_length

Returns the maximum length of an index name.

#indexes_per_table

Returns the maximum number of indexes per table.

#joins_per_query

Returns maximum number of joins in a single query.

#sql_query_length

Returns the maximum length of an SQL query.

#table_alias_length

Returns the maximum length of a table alias.

#table_name_length

Returns the maximum length of a table name.

Quoting - Included

#quote

Quotes the column value to help prevent SQL injection attacks.

#quote_column_name

Quotes the column name.

#quote_string

Quotes a string, escaping any ' (single quote) and \ (backslash) characters.

#quote_table_name

Quotes the table name.

#quote_table_name_for_assignment

Override to return the quoted table name for assignment.

#quoted_date, #quoted_false, #quoted_true,
#type_cast

Cast a value to a type that the database understands.

#unquoted_false, #unquoted_true

DatabaseStatements - Included

#add_transaction_record

Register a record with the current transaction so that its after_commit and after_rollback callbacks can be called.

#begin_db_transaction

Begins the transaction (and turns off auto-committing).

#begin_isolated_db_transaction

Begins the transaction with the isolation level set.

#commit_db_transaction

Commits the transaction (and turns on auto-committing).

#default_sequence_name,
#delete

Executes the delete statement and returns the number of rows affected.

#empty_insert_statement_value,
#exec_delete

Executes delete sql statement in the context of this connection using binds as the bind substitutes.

#exec_insert

Executes insert sql statement in the context of this connection using binds as the bind substitutes.

#exec_query

Executes sql statement in the context of this connection using binds as the bind substitutes.

#exec_update

Executes update sql statement in the context of this connection using binds as the bind substitutes.

#execute

Executes the SQL statement in the context of this connection.

#initialize,
#insert

Returns the last auto-generated ID from the affected table.

#insert_fixture

Inserts the given fixture into the table.

#reset_sequence!

Set the sequence to the max value of the table's column.

#rollback_db_transaction

Rolls back the transaction (and turns on auto-committing).

#rollback_to_savepoint,
#sanitize_limit

Sanitizes the given LIMIT parameter in order to prevent SQL injection.

#select_all

Returns an ::ActiveRecord::Result instance.

#select_one

Returns a record hash with the column names as keys and column values as values.

#select_rows

Returns an array of arrays containing the field values.

#select_value

Returns a single value from a record.

#select_values

Returns an array of the values of the first column in a select:

#to_sql

Converts an arel AST to SQL.

#transaction

Runs the given block in a database transaction, and returns the result of the block.

#transaction_isolation_levels, #transaction_state,
#truncate

Executes the truncate statement.

#update

Executes the update statement and returns the number of rows affected.

SchemaStatements - Included

#add_belongs_to
#add_column

Adds a new column to the named table.

#add_foreign_key

Adds a new foreign key.

#add_index

Adds a new index to the table.

#add_reference

Adds a reference.

#add_timestamps

Adds timestamps (created_at and updated_at) columns to table_name.

#assume_migrated_upto_version,
#change_column

Changes the column's definition according to the new options.

#change_column_default

Sets a new default value for a column:

#change_column_null

Sets or removes a NOT NULL constraint on a column.

#change_table

A block for changing columns in table.

#column_exists?

Checks to see if a column exists in a given table.

#columns

Returns an array of Column objects for the table specified by table_name.

#create_join_table

Creates a new join table with the name created using the lexical order of the first two arguments.

#create_table

Creates a new table with the name table_name.

#data_source_exists?

Checks to see if the data source name exists on the database.

#data_sources

Returns the relation names useable to back Active Record models.

#drop_join_table

Drops the join table specified by the given arguments.

#drop_table

Drops a table from the database.

#foreign_keys

Returns an array of foreign keys for the given table.

#index_exists?

Checks to see if an index exists on a table for a given index definition.

#index_name_exists?

Verifies the existence of an index with a given name.

#initialize_schema_migrations_table

Should not be called normally, but this operation is non-destructive.

#native_database_types

Returns a hash of mappings from the abstract data types to the native database types.

#remove_belongs_to
#remove_column

Removes the column from the table definition.

#remove_columns

Removes the given columns from the table definition.

#remove_foreign_key

Removes the given foreign key from the table.

#remove_index

Removes the given index from the table.

#remove_reference

Removes the reference(s).

#remove_timestamps

Removes the timestamp columns (created_at and updated_at) from the table definition.

#rename_column

Renames a column.

#rename_index

Renames an index.

#rename_table

Renames a table.

#table_alias_for

Truncates a table alias according to the limits of the current adapter.

#table_exists?

Checks to see if the table table_name exists on the database.

Constructor Details

.new(connection, logger, connection_options, config) ⇒ SQLite3Adapter

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 112

def initialize(connection, logger, connection_options, config)
  super(connection, logger)

  @active     = nil
  @statements = StatementPool.new(@connection,
                                  self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 }))
  @config = config

  @visitor = Arel::Visitors::SQLite.new self

  if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
    @prepared_statements = true
  else
    @prepared_statements = false
  end
end

Instance Attribute Details

#active?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 164

def active?
  @active != false
end

#requires_reloading?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 156

def requires_reloading?
  true
end

#supports_ddl_transactions?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 129

def supports_ddl_transactions?
  true
end

#supports_explain?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 201

def supports_explain?
  true
end

#supports_index_sort_order?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 181

def supports_index_sort_order?
  true
end

#supports_partial_index?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 137

def supports_partial_index?
  sqlite_version >= '3.8.0'
end

#supports_savepoints?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 133

def supports_savepoints?
  true
end

#supports_statement_cache?Boolean (readonly)

Returns true, since this connection adapter supports prepared statement caching.

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 143

def supports_statement_cache?
  true
end

#supports_views?Boolean (readonly)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 160

def supports_views?
  true
end

Instance Method Details

#allowed_index_name_length

Returns 62. SQLite supports index names up to 64 characters. The rest is used by rails internally to perform temporary rename operations

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 188

def allowed_index_name_length
  index_name_length - 2
end

#change_column_null(table_name, column_name, null, default = nil)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 463

def change_column_null(table_name, column_name, null, default = nil)
  unless null || default.nil?
    exec_query("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end
  alter_table(table_name) do |definition|
    definition[column_name].null = null
  end
end

#clear_cache!

Clears the prepared statements cache.

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 177

def clear_cache!
  @statements.clear
end

#create(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)

Alias for #insert_sql.

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 334

alias :create :insert_sql

#data_source_exists?(table_name)

Alias for #table_exists?.

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 371

alias data_source_exists? table_exists?

#data_sources(name = nil, table_name = nil)

Alias for #tables.

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 366

alias data_sources tables

#disconnect!

Disconnects from the database if already connected. Otherwise, this method does nothing.

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 170

def disconnect!
  super
  @active = false
  @connection.close rescue nil
end

#encoding

Returns the current database encoding format as a string, eg: 'UTF-8'

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 197

def encoding
  @connection.encoding.to_s
end

#exec_delete(sql, name = 'SQL', binds = []) Also known as: #exec_update

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 306

def exec_delete(sql, name = 'SQL', binds = [])
  exec_query(sql, name, binds)
  @connection.changes
end

#exec_query(sql, name = nil, binds = [])

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 276

def exec_query(sql, name = nil, binds = [])
  type_casted_binds = binds.map { |col, val|
    [col, type_cast(val, col)]
  }

  log(sql, name, type_casted_binds) do
    # Don't cache statements if they are not prepared
    if without_prepared_statement?(binds)
      stmt    = @connection.prepare(sql)
      begin
        cols    = stmt.columns
        records = stmt.to_a
      ensure
        stmt.close
      end
      stmt = records
    else
      cache = @statements[sql] ||= {
        :stmt => @connection.prepare(sql)
      }
      stmt = cache[:stmt]
      cols = cache[:cols] ||= stmt.columns
      stmt.reset!
      stmt.bind_params type_casted_binds.map { |_, val| val }
    end

    ActiveRecord::Result.new(cols, stmt.to_a)
  end
end

#exec_update(sql, name = 'SQL', binds = [])

Alias for #exec_delete.

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 310

alias :exec_update :exec_delete

#explain(arel, binds = [])

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 257

def explain(arel, binds = [])
  sql = "EXPLAIN QUERY PLAN #{to_sql(arel, binds)}"
  ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', []))
end

#last_inserted_id(result)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 312

def last_inserted_id(result)
  @connection.last_insert_row_id
end

#quote_table_name_for_assignment(table, attr)

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 235

def quote_table_name_for_assignment(table, attr)
  quote_column_name(attr)
end

#rename_table(table_name, new_name)

Renames a table.

Example:

rename_table('octopuses', 'octopi')
[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 430

def rename_table(table_name, new_name)
  exec_query "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
  rename_table_indexes(table_name, new_name)
end

#select_rows(sql, name = nil, binds = [])

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 336

def select_rows(sql, name = nil, binds = [])
  exec_query(sql, name, binds).rows
end

#table_exists?(table_name) ⇒ Boolean Also known as: #data_source_exists?

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 368

def table_exists?(table_name)
  table_name && tables(nil, table_name).any?
end

#valid_alter_table_type?(type) ⇒ Boolean

See: www.sqlite.org/lang_altertable.html SQLite has an additional restriction on the ALTER TABLE statement

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb', line 437

def valid_alter_table_type?(type)
  type.to_sym != :primary_key
end