класс ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 206
def begin_db_transaction
  execute "BEGIN"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 210
def begin_isolated_db_transaction(isolation)
  execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
  begin_db_transaction
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 270
def charset
  show_variable "character_set_database"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 275
def collation
  show_variable "collation_database"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 245
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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 265
def current_database
  query_value("SELECT database()", "SCHEMA")
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 320
def drop_table(table_name, options = {})
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 223
def empty_insert_statement_value(primary_key = nil)
  "VALUES ()"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 189
def execute(sql, name = nil)
  materialize_transactions

  log(sql, name) do
    ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
      @connection.query(sql)
    end
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 179
def explain(arel, binds = [])
  sql     = "EXPLAIN #{to_sql(arel, binds)}"
  start   = Concurrent.monotonic_time
  result  = exec_query(sql, "EXPLAIN", binds)
  elapsed = Concurrent.monotonic_time - start

  MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 372
      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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 137
def index_algorithms
  { default: +"ALGORITHM = DEFAULT", copy: +"ALGORITHM = COPY", inplace: +"ALGORITHM = INPLACE" }
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 133
def native_database_types
  NATIVE_DATABASE_TYPES
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 231
def recreate_database(name, options = {})
  drop_database(name)
  sql = create_database(name, options)
  reconnect!
  sql
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 324
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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 300
def rename_table(table_name, new_name)
  execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
  rename_table_indexes(table_name, new_name)
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 430
def show_variable(name)
  query_value("SELECT @@#{name}", "SCHEMA")
rescue ActiveRecord::StatementInvalid
  nil
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 496
def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 113
def supports_advisory_locks?
  true
end

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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 100
def supports_datetime_with_precision?
  mariadb? || database_version >= "5.6.4"
end

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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 76
def supports_expression_index?
  !mariadb? && database_version >= "8.0.13"
end

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

# 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

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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 117
def supports_insert_on_duplicate_skip?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 121
def supports_insert_on_duplicate_update?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 109
def supports_optimizer_hints?
  !mariadb? && database_version >= "5.7.7"
end

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

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 96
def supports_views?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 104
def supports_virtual_columns?
  mariadb? || database_version >= "5.7.5"
end