class ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

Constants

CR_SERVER_GONE_ERROR
CR_SERVER_LOST
EMULATE_BOOLEANS_TRUE
ER_CANNOT_ADD_FOREIGN
ER_CANNOT_CREATE_TABLE
ER_CHECK_CONSTRAINT_VIOLATED
ER_CLIENT_INTERACTION_TIMEOUT
ER_CONNECTION_KILLED
ER_CONSTRAINT_FAILED
ER_DATA_TOO_LONG
ER_DB_CREATE_EXISTS: See dev.mysql.com/doc/mysql-errors/en/server-error-reference.html
ER_DO_NOT_HAVE_DEFAULT
ER_DUP_ENTRY
ER_FILSORT_ABORT
ER_FK_INCOMPATIBLE_COLUMNS
ER_LOCK_DEADLOCK
ER_LOCK_WAIT_TIMEOUT
ER_NOT_NULL_VIOLATION
ER_NO_DB_ERROR
ER_NO_REFERENCED_ROW
ER_NO_REFERENCED_ROW_2
ER_OUT_OF_RANGE
ER_QUERY_INTERRUPTED
ER_QUERY_TIMEOUT
ER_ROW_IS_REFERENCED
ER_ROW_IS_REFERENCED_2
ER_SERVER_SHUTDOWN
EXTENDED_TYPE_MAPS
NATIVE_DATABASE_TYPES

Public Class Methods

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 76
def dbconsole(config, options = {})
  mysql_config = config.configuration_hash

  args = cli_args(mysql_config.except(:password))

  if mysql_config[:password] && options[:include_password]
    args << "--password=#{mysql_config[:password]}"
  elsif mysql_config[:password] && !mysql_config[:password].to_s.empty?
    args << "-p"
  end

  args << config.database

  find_cmd_and_exec(ActiveRecord.database_cli[:mysql], *args)
end

emulate_booleans ()

By default, the Mysql2Adapter will consider all columns of type tinyint(1) as boolean. If you wish to disable this emulation you can add the following line to your application.rb file:

ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans = false

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 29
class_attribute :emulate_booleans, default: true

Public Instance Methods

charset ()

Returns the database character set.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 338
def charset
  show_variable "character_set_database"
end

check_constraints (table_name)

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 565
      def check_constraints(table_name)
        if supports_check_constraints?
          scope = quoted_scope(table_name)

          sql = <<~SQL
            SELECT cc.constraint_name AS 'name',
                  cc.check_clause AS 'expression'
            FROM information_schema.check_constraints cc
            JOIN information_schema.table_constraints tc
            USING (constraint_schema, constraint_name)
            WHERE tc.table_schema = #{scope[:schema]}
              AND tc.table_name = #{scope[:name]}
              AND cc.constraint_schema = #{scope[:schema]}
          SQL
          sql += " AND cc.table_name = #{scope[:name]}" if mariadb?

          chk_info = internal_exec_query(sql, "SCHEMA")

          chk_info.map do |row|
            options = {
              name: row["name"]
            }
            expression = row["expression"]
            expression = expression[1..-2] if expression.start_with?("(") && expression.end_with?(")")
            expression = strip_whitespace_characters(expression)

            unless mariadb?
              # MySQL returns check constraints expression in an already escaped form.
              # This leads to duplicate escaping later (e.g. when the expression is used in the SchemaDumper).
              expression = expression.gsub("\\'", "'")
            end

            CheckConstraintDefinition.new(table_name, expression, options)
          end
        else
          raise NotImplementedError
        end
      end

collation ()

Returns the database collation strategy.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 343
def collation
  show_variable "collation_database"
end

create_database (name, options = {})

Create a new MySQL database with optional :charset and :collation. Charset defaults to utf8mb4.

Example:

create_database 'charset_test', charset: 'latin1', collation: 'latin1_bin'
create_database 'matt_development'
create_database 'matt_development', charset: :big5

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 313
def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT COLLATE #{quote_table_name(options[:collation])}"
  elsif options[:charset]
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset])}"
  elsif row_format_dynamic_by_default?
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET `utf8mb4`"
  else
    raise "Configure a supported :charset and ensure innodb_large_prefix is enabled to support indexes on varchar(255) string columns."
  end
end

current_database ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 333
def current_database
  query_value("SELECT database()", "SCHEMA")
end

drop_table (*table_names, **options)

Drops a table or tables from the database.

:force: Set to :cascade to drop dependent objects as well. Defaults to false.
:if_exists: Set to true to only drop the table if it exists. Defaults to false.
:temporary: Set to true to drop temporary table. Defaults to false.

Although this command ignores most options and the block if one is given, it can be helpful to provide these in a migration’s change method so it can be reverted. In that case, options and the block will be used by create_table except if you provide more than one table which is not supported.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 391
def drop_table(*table_names, **options)
  table_names.each { |table_name| schema_cache.clear_data_source_cache!(table_name.to_s) }
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{table_names.map { |table_name| quote_table_name(table_name) }.join(', ')}#{' CASCADE' if options[:force] == :cascade}"
end

foreign_keys (table_name)

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 520
      def foreign_keys(table_name)
        raise ArgumentError unless table_name.present?

        scope = quoted_scope(table_name)

        # MySQL returns 1 row for each column of composite foreign keys.
        fk_info = internal_exec_query(<<~SQL, "SCHEMA")
          SELECT fk.referenced_table_name AS 'to_table',
                 fk.referenced_column_name AS 'primary_key',
                 fk.column_name AS 'column',
                 fk.constraint_name AS 'name',
                 fk.ordinal_position AS 'position',
                 rc.update_rule AS 'on_update',
                 rc.delete_rule AS 'on_delete'
          FROM information_schema.referential_constraints rc
          JOIN information_schema.key_column_usage fk
          USING (constraint_schema, constraint_name)
          WHERE fk.referenced_column_name IS NOT NULL
            AND fk.table_schema = #{scope[:schema]}
            AND fk.table_name = #{scope[:name]}
            AND rc.constraint_schema = #{scope[:schema]}
            AND rc.table_name = #{scope[:name]}
        SQL

        grouped_fk = fk_info.group_by { |row| row["name"] }.values.each { |group| group.sort_by! { |row| row["position"] } }
        grouped_fk.map do |group|
          row = group.first
          options = {
            name: row["name"],
            on_update: extract_foreign_key_action(row["on_update"]),
            on_delete: extract_foreign_key_action(row["on_delete"])
          }

          if group.one?
            options[:column] = unquote_identifier(row["column"])
            options[:primary_key] = row["primary_key"]
          else
            options[:column] = group.map { |row| unquote_identifier(row["column"]) }
            options[:primary_key] = group.map { |row| row["primary_key"] }
          end

          ForeignKeyDefinition.new(table_name, unquote_identifier(row["to_table"]), options)
        end
      end

index_algorithms ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 220
def index_algorithms
  {
    default: "ALGORITHM = DEFAULT",
    copy:    "ALGORITHM = COPY",
    inplace: "ALGORITHM = INPLACE",
    instant: "ALGORITHM = INSTANT",
  }
end

quote_string (string)

Quotes strings for use in SQL input.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 750
def quote_string(string)
  with_raw_connection(allow_retry: true, materialize_transactions: false) do |connection|
    connection.escape(string)
  end
end

recreate_database (name, options = {})

Drops the database specified on the name attribute and creates it again using the provided options.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 299
def recreate_database(name, options = {})
  drop_database(name)
  sql = create_database(name, options)
  reconnect!
  sql
end

rename_index (table_name, old_name, new_name)

Calls superclass method

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 396
def rename_index(table_name, old_name, new_name)
  if supports_rename_index?
    validate_index_length!(table_name, new_name)

    execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"
  else
    super
  end
end

rename_table (table_name, new_name, **options)

Renames a table.

Example:

rename_table('octopuses', 'octopi')

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 368
def rename_table(table_name, new_name, **options)
  validate_table_length!(new_name) unless options[:_uses_legacy_table_name]
  schema_cache.clear_data_source_cache!(table_name.to_s)
  schema_cache.clear_data_source_cache!(new_name.to_s)
  execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
  rename_table_indexes(table_name, new_name, **options)
end

show_variable (name)

SHOW VARIABLES LIKE ‘name’

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 634
def show_variable(name)
  query_value("SELECT @@#{name}", "SCHEMA", materialize_transactions: false, allow_retry: true)
rescue ActiveRecord::StatementInvalid
  nil
end

strict_mode? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 685
def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end

supports_advisory_locks? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 172
def supports_advisory_locks?
  true
end

supports_bulk_alter? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 107
def supports_bulk_alter?
  true
end

supports_check_constraints? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 139
def supports_check_constraints?
  if mariadb?
    database_version >= "10.3.10" || (database_version < "10.3" && database_version >= "10.2.22")
  else
    database_version >= "8.0.16"
  end
end

supports_common_table_expressions? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 164
def supports_common_table_expressions?
  if mariadb?
    database_version >= "10.2.1"
  else
    database_version >= "8.0.1"
  end
end

supports_datetime_with_precision? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 151
def supports_datetime_with_precision?
  true
end

supports_disabling_indexes? ()

See dev.mysql.com/doc/refman/8.0/en/invisible-indexes.html for more details on MySQL feature. See mariadb.com/kb/en/ignored-indexes/ for more details on the MariaDB feature.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 194
def supports_disabling_indexes?
  if mariadb?
    database_version >= "10.6.0"
  else
    database_version >= "8.0.0"
  end
end

supports_explain? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 127
def supports_explain?
  true
end

supports_expression_index? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 115
def supports_expression_index?
  !mariadb? && database_version >= "8.0.13"
end

supports_foreign_keys? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 135
def supports_foreign_keys?
  true
end

supports_index_sort_order? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 111
def supports_index_sort_order?
  mariadb? ? database_version >= "10.8.1" : database_version >= "8.0.1"
end

supports_indexes_in_create? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 131
def supports_indexes_in_create?
  true
end

supports_insert_on_duplicate_skip? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 176
def supports_insert_on_duplicate_skip?
  true
end

supports_insert_on_duplicate_update? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 180
def supports_insert_on_duplicate_update?
  true
end

supports_insert_returning? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 184
def supports_insert_returning?
  mariadb? && database_version >= "10.5.0"
end

supports_optimizer_hints? ()

See dev.mysql.com/doc/refman/en/optimizer-hints.html for more details.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 160
def supports_optimizer_hints?
  !mariadb? && database_version >= "5.7.7"
end

supports_restart_db_transaction? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 123
def supports_restart_db_transaction?
  true
end

supports_transaction_isolation? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 119
def supports_transaction_isolation?
  true
end

supports_views? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 147
def supports_views?
  true
end

supports_virtual_columns? ()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 155
def supports_virtual_columns?
  mariadb? || database_version >= "5.7.5"
end