Method after_transaction_create

lib/sqlalchemy/orm/events.py:1735–1776

Execute when a new :class:`.SessionTransaction` is created. This event differs from :meth:`~.SessionEvents.after_begin` in that it occurs for each :class:`.SessionTransaction` overall, as opposed to when transactions are begun on individual database connections. It

(
        self, session: Session, transaction: SessionTransaction
    )

        """

    def after_transaction_create(
        self, session: Session, transaction: SessionTransaction
    ) -> None:
        """Execute when a new :class:`.SessionTransaction` is created.

        This event differs from :meth:`~.SessionEvents.after_begin`
        in that it occurs for each :class:`.SessionTransaction`
        overall, as opposed to when transactions are begun
        on individual database connections.  It is also invoked
        for nested transactions and subtransactions, and is always
        matched by a corresponding
        :meth:`~.SessionEvents.after_transaction_end` event
        (assuming normal operation of the :class:`.Session`).

        :param session: the target :class:`.Session`.
        :param transaction: the target :class:`.SessionTransaction`.

         To detect if this is the outermost
         :class:`.SessionTransaction`, as opposed to a "subtransaction" or a
         SAVEPOINT, test that the :attr:`.SessionTransaction.parent` attribute
         is ``None``::

                @event.listens_for(session, "after_transaction_create")
                def after_transaction_create(session, transaction):
                    if transaction.parent is None:
                        ...  # work with top-level transaction

         To detect if the :class:`.SessionTransaction` is a SAVEPOINT, use the
         :attr:`.SessionTransaction.nested` attribute::

                @event.listens_for(session, "after_transaction_create")
                def after_transaction_create(session, transaction):
                    if transaction.nested:
                        ...  # work with SAVEPOINT transaction

        .. seealso::

            :class:`.SessionTransaction`

            :meth:`~.SessionEvents.after_transaction_end`

        """

    def after_transaction_end(
        self, session: Session, transaction: SessionTransaction