On Tue, Sep 18, 2018 at 7:07 AM Dmytro Starosud <d.staro...@gmail.com> wrote:
>
> Hello group
>
> Please help me with the following. Imagine I have:
>
> @event.listens_for(Session, 'before_flush')
> def one(session, flush_context, instances):
> pass
>
>
> @event.listens_for(Session, 'before_flush')
> def two(session, flush_context, instances):
> pass
>
>
> I.e. two handlers for the same target/identifier are registered in a row.
> Will they be executed in the order they registered?
> Is this order actually strictly specified?
> Documentation link would be great, as I failed to find this in docs.
The handlers are registered in order and are called in the order they
were registered. however it's not quite in the "spirit" of the event
system to rely upon this. For example, someone could someday be
refactoring your code above and then "two" gets placed above "one",
since these are two functions that don't have any obvious relationship
to each other. So I wouldn't recommend that pattern just from a
Python perspective.
if you have two event handling functions with a dependency between
each other, it's much better to make this explicit in your code, and
do something like:
@event.listens_for(Session, "before_flush")
def both(...):
one(...)
two(...)
>
> Thanks a lot in advance!
> Best regards
> Dmytro
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
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SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
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