Class: ActiveRecord::ConnectionAdapters::Mysql2Adapter

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, `AbstractMysqlAdapter`, `AbstractAdapter`, `::ActiveSupport::DescendantsTracker`
Instance Chain: self, `MySQL::DatabaseStatements`, `AbstractMysqlAdapter`, `AbstractAdapter`, `Savepoints`, `::ActiveRecord::QueryCache`, `DatabaseLimits`, `Quoting`, `DatabaseStatements`, `SchemaStatements`, `::ActiveSupport::Callbacks`
Inherits:	ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter `::Object` ActiveRecord::ConnectionAdapters::AbstractAdapter ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter ActiveRecord::ConnectionAdapters::Mysql2Adapter
Defined in:	activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb

Constant Summary

ADAPTER_NAME =
# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 35
```
"Mysql2".freeze
```

Class Attribute Summary

`AbstractMysqlAdapter` - Inherited

.emulate_booleans, .emulate_booleans?

`AbstractAdapter` - Inherited

.__callbacks, .__callbacks?

Class Method Summary

.new(connection, logger, connection_options, config) ⇒ Mysql2Adapter constructor

`AbstractMysqlAdapter` - Inherited

.new

`AbstractAdapter` - Inherited

.type_cast_config_to_boolean, .type_cast_config_to_integer

`::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

#active? ⇒ Boolean readonly
#supports_comments? ⇒ Boolean readonly
#supports_comments_in_create? ⇒ Boolean readonly
#supports_json? ⇒ Boolean readonly
#supports_savepoints? ⇒ Boolean readonly

`AbstractMysqlAdapter` - Inherited

#emulate_booleans, #emulate_booleans?, #strict_mode?, #supports_advisory_locks?, #supports_datetime_with_precision?, #supports_explain?, #supports_foreign_keys?, #supports_index_sort_order?, #supports_indexes_in_create?, #supports_transaction_isolation?, #supports_views?, #supports_virtual_columns?

`AbstractAdapter` - Inherited

#__callbacks, #__callbacks?,
#active?	Checks whether the connection to the database is still active.
#in_use?	Alias for AbstractAdapter#owner.
#lock, #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_advisory_locks?	Does this adapter support application-enforced advisory locking?
#supports_bulk_alter?,
#supports_comments?	Does this adapter support metadata comments on database objects (tables, columns, indexes)?
#supports_comments_in_create?	Can comments for tables, columns, and indexes be specified in create/alter table statements?
#supports_datetime_with_precision?	Does this adapter support datetime with precision?
#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_expression_index?	Does this adapter support expression indices?
#supports_extensions?	Does this adapter support database extensions?
#supports_foreign_keys?	Does this adapter support creating foreign key constraints?
#supports_foreign_keys_in_create?	Does this adapter support creating foreign key constraints in the same statement as creating the table?
#supports_foreign_tables?	Does this adapter support foreign/external tables?
#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_json?	Does this adapter support json data type?
#supports_multi_insert?	Does this adapter support multi-value insert?
#supports_partial_index?	Does this adapter support partial indices?
#supports_savepoints?	Does this adapter support savepoints?
#supports_transaction_isolation?	Does this adapter support setting the isolation level for a transaction?
#supports_validate_constraints?	Does this adapter support creating invalid constraints?
#supports_views?	Does this adapter support views?
#supports_virtual_columns?	Does this adapter support virtual columns?
#visitor

`DatabaseStatements` - Included

#begin_transaction, #commit_transaction, #current_transaction, #open_transactions, #rollback_transaction, #transaction_open?, #within_new_transaction

Instance Method Summary

#disconnect!

Disconnects from the database if already connected.
#error_number(exception)
#quote_string(string)
#reconnect! (also: #reset!)
#reset!

Alias for #reconnect!.

`MySQL::DatabaseStatements` - Included

#exec_delete, #exec_query,
#exec_update	Alias for MySQL::DatabaseStatements#exec_delete.
#execute	Executes the SQL statement in the context of this connection.

`AbstractMysqlAdapter` - Inherited

#begin_db_transaction, #begin_isolated_db_transaction,
#charset	Returns the database character set.
#clear_cache!	Clears the prepared statements cache.
#collation	Returns the database collation strategy.
#create_database	Create a new `MySQL` database with optional `:charset` and `:collation`.
#current_database,
#drop_table	Drops a table from the database.
#empty_insert_statement_value,
#execute	Executes the SQL statement in the context of this connection.
#explain, #foreign_keys, #index_algorithms, #insert_fixtures_set, #native_database_types,
#recreate_database	Drops the database specified on the `name` attribute and creates it again using the provided `options`.
#rename_index,
#rename_table	Renames a table.
#show_variable	SHOW VARIABLES LIKE ‘name’.
#truncate

`AbstractAdapter` - Inherited

#adapter_name	Returns the human-readable name of the adapter.
#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.
#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`.
#discard!	Immediately forget this connection ever existed.
#disconnect!	Disconnects from the database if already connected.
#enable_extension	This is meant to be implemented by the adapters that support extensions.
#expire	this method must only be called while holding connection pool’s mutex.
#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	this method must only be called while holding connection pool’s mutex.
#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.
#reset!	Reset the state of this connection, directing the DBMS to clear transactions and other connection-related server-side state.
#unprepared_statement,
#verify!	Checks whether the connection to the database is still active (i.e. not stale).
#log

`Savepoints` - Included

#create_savepoint, #current_savepoint_name, #exec_rollback_to_savepoint, #release_savepoint

`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	Quote date/time values for use in SQL input.
#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).
#create	Alias for DatabaseStatements#insert.
#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 and returns the raw result from the connection adapter.
#initialize,
#insert	Executes an INSERT query and returns the new record’s ID.
#insert_fixture	Inserts the given fixture into the table.
#insert_fixtures	Inserts a set of fixtures into the table.
#insert_fixtures_set,
#join_to_delete	Alias for DatabaseStatements#join_to_update.
#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	Alias for SchemaStatements#add_reference.
#add_column	Add a new `type` column named `column_name` to `table_name`.
#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_comment	Changes the comment for a column or removes it if `nil`.
#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`.
#change_table_comment	Changes the comment for a table or removes it if `nil`.
#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_key_exists?	Checks to see if a foreign key exists on a table for a given foreign key definition.
#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.
#indexes	Returns an array of indexes for the given table.
#native_database_types	Returns a hash of mappings from the abstract data types to the native database types.
#options_include_default?,
#primary_key	Returns just a table’s primary key.
#remove_belongs_to	Alias for SchemaStatements#remove_reference.
#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_comment	Returns the table comment that’s stored in database metadata.
#table_exists?	Checks to see if the table `table_name` exists on the database.
#table_options,
#tables	Returns an array of table names defined in the database.
#view_exists?	Checks to see if the view `view_name` exists on the database.
#views	Returns an array of view names defined in the database.

`::ActiveSupport::Callbacks` - Included

#run_callbacks

Runs the callbacks for the given event.

Constructor Details

.new(connection, logger, connection_options, config) ⇒ `Mysql2Adapter`

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 39


def initialize(connection, logger, connection_options, config)
  super
  @prepared_statements = false unless config.key?(:prepared_statements)
  configure_connection
end

Instance Attribute Details

#active? ⇒ `Boolean` (readonly)

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 89


def active?
  @connection.ping
end

#supports_comments? ⇒ `Boolean` (readonly)

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 49


def supports_comments?
  true
end

#supports_comments_in_create? ⇒ `Boolean` (readonly)

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 53


def supports_comments_in_create?
  true
end

#supports_json? ⇒ `Boolean` (readonly)

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 45


def supports_json?
  !mariadb? && version >= "5.7.8"
end

#supports_savepoints? ⇒ `Boolean` (readonly)

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 57


def supports_savepoints?
  true
end

Instance Method Details

#disconnect!

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

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 102


def disconnect!
  super
  @connection.close
end

#error_number(exception)

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 73


def error_number(exception)
  exception.error_number if exception.respond_to?(:error_number)
end

#quote_string(string)

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 81


def quote_string(string)
  @connection.escape(string)
end

#reconnect! Also known as: #reset!

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 93


def reconnect!
  super
  disconnect!
  connect
end

#reset!

Alias for #reconnect!.

[ GitHub ]

# File 'activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb', line 98


alias :reset! :reconnect!

Class: ActiveRecord::ConnectionAdapters::Mysql2Adapter

Constant Summary

::ActiveSupport::Callbacks - Included

AbstractAdapter - Inherited

AbstractMysqlAdapter - Inherited

Class Attribute Summary

AbstractMysqlAdapter - Inherited

AbstractAdapter - Inherited

Class Method Summary

AbstractMysqlAdapter - Inherited

AbstractAdapter - Inherited

::ActiveSupport::DescendantsTracker - Inherited

Instance Attribute Summary

AbstractMysqlAdapter - Inherited

AbstractAdapter - Inherited

DatabaseStatements - Included

Instance Method Summary

MySQL::DatabaseStatements - Included

AbstractMysqlAdapter - Inherited

AbstractAdapter - Inherited

Savepoints - Included

DatabaseLimits - Included

Quoting - Included

DatabaseStatements - Included

SchemaStatements - Included

::ActiveSupport::Callbacks - Included

Constructor Details

.new(connection, logger, connection_options, config) ⇒ Mysql2Adapter

Instance Attribute Details

#active? ⇒ Boolean (readonly)

#supports_comments? ⇒ Boolean (readonly)

#supports_comments_in_create? ⇒ Boolean (readonly)

#supports_json? ⇒ Boolean (readonly)

#supports_savepoints? ⇒ Boolean (readonly)

Instance Method Details

#disconnect!

#error_number(exception)

#quote_string(string)

#reconnect! Also known as: #reset!

#reset!

`::ActiveSupport::Callbacks` - Included

`AbstractAdapter` - Inherited

`AbstractMysqlAdapter` - Inherited

`AbstractMysqlAdapter` - Inherited

`AbstractAdapter` - Inherited

`AbstractMysqlAdapter` - Inherited

`AbstractAdapter` - Inherited

`::ActiveSupport::DescendantsTracker` - Inherited

`AbstractMysqlAdapter` - Inherited

`AbstractAdapter` - Inherited

`DatabaseStatements` - Included

`MySQL::DatabaseStatements` - Included

`AbstractMysqlAdapter` - Inherited

`AbstractAdapter` - Inherited

`Savepoints` - Included

`DatabaseLimits` - Included

`Quoting` - Included

`DatabaseStatements` - Included

`SchemaStatements` - Included

`::ActiveSupport::Callbacks` - Included

.new(connection, logger, connection_options, config) ⇒ `Mysql2Adapter`

#active? ⇒ `Boolean` (readonly)

#supports_comments? ⇒ `Boolean` (readonly)

#supports_comments_in_create? ⇒ `Boolean` (readonly)

#supports_json? ⇒ `Boolean` (readonly)

#supports_savepoints? ⇒ `Boolean` (readonly)