Method begin_twophase

lib/sqlalchemy/engine/base.py:961–989

Begin a two-phase or XA transaction and return a transaction handle. The returned object is an instance of :class:`.TwoPhaseTransaction`, which in addition to the methods provided by :class:`.Transaction`, also provides a :meth:`~.TwoPhaseTransaction.prepare`

(self, xid: Optional[Any] = None)

        return NestedTransaction(self)

    def begin_twophase(self, xid: Optional[Any] = None) -> TwoPhaseTransaction:
        """Begin a two-phase or XA transaction and return a transaction
        handle.

        The returned object is an instance of :class:`.TwoPhaseTransaction`,
        which in addition to the methods provided by
        :class:`.Transaction`, also provides a
        :meth:`~.TwoPhaseTransaction.prepare` method.

        :param xid: the two phase transaction id.  If not supplied, a
          random id will be generated. The accepted type and value depends on
          the driver in use.

        .. seealso::

            :meth:`_engine.Connection.begin`

            :meth:`_engine.Connection.begin_twophase`

        """

        if self._transaction is not None:
            raise exc.InvalidRequestError(
                "Cannot start a two phase transaction when a transaction "
                "is already in progress."
            )
        if xid is None:
            xid = self.engine.dialect.create_xid()
        return TwoPhaseTransaction(self, xid)

    def commit(self) -> None:
        """Commit the transaction that is currently in progress.