Methods

Constants

ER_CANNOT_ADD_FOREIGN = 1215
 
ER_CANNOT_CREATE_TABLE = 1005
 
ER_DATA_TOO_LONG = 1406
 
ER_DB_CREATE_EXISTS = 1007
 

See dev.mysql.com/doc/mysql-errors/en/server-error-reference.html

ER_DO_NOT_HAVE_DEFAULT = 1364
 
ER_DUP_ENTRY = 1062
 
ER_FILSORT_ABORT = 1028
 
ER_FK_INCOMPATIBLE_COLUMNS = 3780
 
ER_LOCK_DEADLOCK = 1213
 
ER_LOCK_WAIT_TIMEOUT = 1205
 
ER_NOT_NULL_VIOLATION = 1048
 
ER_NO_REFERENCED_ROW = 1216
 
ER_NO_REFERENCED_ROW_2 = 1452
 
ER_OUT_OF_RANGE = 1264
 
ER_QUERY_INTERRUPTED = 1317
 
ER_QUERY_TIMEOUT = 3024
 
ER_ROW_IS_REFERENCED = 1217
 
ER_ROW_IS_REFERENCED_2 = 1451
 
NATIVE_DATABASE_TYPES = { primary_key: "bigint auto_increment PRIMARY KEY", string: { name: "varchar", limit: 255 }, text: { name: "text" }, integer: { name: "int", limit: 4 }, bigint: { name: "bigint" }, float: { name: "float", limit: 24 }, decimal: { name: "decimal" }, datetime: { name: "datetime" }, timestamp: { name: "timestamp" }, time: { name: "time" }, date: { name: "date" }, binary: { name: "blob" }, blob: { name: "blob" }, boolean: { name: "tinyint", limit: 1 }, json: { name: "json" }, }
 
TYPE_MAP = Type::TypeMap.new.tap { |m| initialize_type_map(m) }
 
TYPE_MAP_WITH_BOOLEAN = Type::TypeMap.new(TYPE_MAP).tap do |m| m.register_type %r(^tinyint\(1\))i, Type::Boolean.new end
 

Class Public methods

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 27
class_attribute :emulate_booleans, default: true

new(connection, logger, connection_options, config)

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 54
def initialize(connection, logger, connection_options, config)
  super(connection, logger, config)
end

Instance Public methods

charset()

Returns the database character set.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 274
def charset
  show_variable "character_set_database"
end

check_constraints(table_name)

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 418
      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 = exec_query(sql, "SCHEMA")

          chk_info.map do |row|
            options = {
              name: row["name"]
            }
            expression = row["expression"]
            expression = expression[1..-2] unless mariadb? # remove parentheses added by mysql
            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 279
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 249
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 269
def current_database
  query_value("SELECT database()", "SCHEMA")
end

drop_table(table_name, **options)

Drops a table 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.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 326
def drop_table(table_name, **options)
  schema_cache.clear_data_source_cache!(table_name.to_s)
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end

execute(sql, name = nil, async: false)

Executes the SQL statement in the context of this connection.

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 199
def execute(sql, name = nil, async: false)
  raw_execute(sql, name, async: async)
end

foreign_keys(table_name)

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 382
      def foreign_keys(table_name)
        raise ArgumentError unless table_name.present?

        scope = quoted_scope(table_name)

        fk_info = 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',
                 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

        fk_info.map do |row|
          options = {
            column: row["column"],
            name: row["name"],
            primary_key: row["primary_key"]
          }

          options[:on_update] = extract_foreign_key_action(row["on_update"])
          options[:on_delete] = extract_foreign_key_action(row["on_delete"])

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

index_algorithms()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 158
def index_algorithms
  {
    default: "ALGORITHM = DEFAULT",
    copy:    "ALGORITHM = COPY",
    inplace: "ALGORITHM = INPLACE",
    instant: "ALGORITHM = INSTANT",
  }
end

native_database_types()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 154
def native_database_types
  NATIVE_DATABASE_TYPES
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 235
def recreate_database(name, options = {})
  drop_database(name)
  sql = create_database(name, options)
  reconnect!
  sql
end

rename_index(table_name, old_name, new_name)

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 331
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)

Renames a table.

Example:

rename_table('octopuses', 'octopi')
# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 304
def rename_table(table_name, new_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)
end

show_variable(name)

SHOW VARIABLES LIKE 'name'

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 479
def show_variable(name)
  query_value("SELECT @@#{name}", "SCHEMA")
rescue ActiveRecord::StatementInvalid
  nil
end

strict_mode?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 530
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 129
def supports_advisory_locks?
  true
end

supports_bulk_alter?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 68
def supports_bulk_alter?
  true
end

supports_check_constraints?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 96
def supports_check_constraints?
  if mariadb?
    database_version >= "10.2.1"
  else
    database_version >= "8.0.16"
  end
end

supports_common_table_expressions?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 121
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 108
def supports_datetime_with_precision?
  mariadb? || database_version >= "5.6.4"
end

supports_explain?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 84
def supports_explain?
  true
end

supports_expression_index?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 76
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 92
def supports_foreign_keys?
  true
end

supports_index_sort_order?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 72
def supports_index_sort_order?
  !mariadb? && database_version >= "8.0.1"
end

supports_indexes_in_create?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 88
def supports_indexes_in_create?
  true
end

supports_insert_on_duplicate_skip?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 133
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 137
def supports_insert_on_duplicate_update?
  true
end

supports_optimizer_hints?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 117
def supports_optimizer_hints?
  !mariadb? && database_version >= "5.7.7"
end

supports_transaction_isolation?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 80
def supports_transaction_isolation?
  true
end

supports_views?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 104
def supports_views?
  true
end

supports_virtual_columns?()

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 112
def supports_virtual_columns?
  mariadb? || database_version >= "5.7.5"
end