begin_nested() can be used within any of the before_flush(), after_flush(), or
after_flush_postexec() methods, see below.
What you can't do in *any* of these methods is flush() the Session itself, as
the Session is already in the flush state and it does not support reentrant
behavior.
Hi there !
I'm going mad looking for a solution for what seems a simple problem.
When object A is updated, I also want object B to be updated, using some
computation based on A new values.
From now, I can detect when A is modified using after_update.
What I try is to look at event
A friend point me out the hybrid_property and the fact I can detect an
update of A fields before doing the commit, issuing some update for B. I'll
try this idea.
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On Aug 30, 2012, at 10:32 AM, Tony Moutaux wrote:
Hi there !
I'm going mad looking for a solution for what seems a simple problem.
When object A is updated, I also want object B to be updated, using some
computation based on A new values.
From now, I can detect when A is modified using
Only if some computation based on A new values means that there are
SQL-level functions which you need to get at, does the rationale for
after_update/after_flush events to come up.Unfortunately you can't
emit a flush() within any of these events, as they are already local to the
On Aug 30, 2012, at 11:12 AM, Tony Moutaux wrote:
2.if some computation involves SQL functions:
a. emit your modifications to B using only SQL statements and
Session.execute(), not by adding any new state to the Session or re-flushing.
b. pre-execute your SQL functions for A
Hello,
We (QNX Software Systems) have an embedded project developed using
SQLAlchemy and using sqlite3 and the database. It works, but needs an
expert hand at tuning, debugging, and optimizing. Looking for someone to
start ASAP. Please send your resume or qualifications to me @
You could use hybrid attributes to do that.
http://docs.sqlalchemy.org/en/rel_0_7/orm/extensions/hybrid.html
On Wednesday, August 29, 2012 5:22:02 PM UTC+9, Denis Rykov wrote:
I have two models:
class Report(Base):
__tablename__ = 'report'
id = Column(Integer,
