On Oct 24, 2007, at 12:17 PM, Kevin Schmidt wrote:
>
> Hello all,
>
> I have a problem using session.merge() in version 0.3.10. I'm
> trying to merge an
> object I'm getting via SOAP from a different server. Here is my code:
>
>
> self._censusTable = Table('census', self._dbMetaData, autoload=True)
> self._censusMapper = mapper(Census, self._censusTable)
> self._session = create_session()
>
>
> def writeCensus(self, soapCensus):
> currentTrans = self._session.create_transaction()
> try:
> sessionCensus = \
> self._session.query(Census).get(soapCensus.id)
> test = self._session.merge(soapCensus)
> currentTrans.commit()
>
> except Exception, e:
> currentTrans.rollback()
>
>
> The result is:
>
> FlushError: New instance [EMAIL PROTECTED] with identity key (<class
> 'census.Census'>, (12347,), None) conflicts with persistent instance
> [EMAIL PROTECTED]
>
> soapCensus is an instance of class Census created by the SOAP
> library (ZSI),
> which should be the same as restoring an object via pickle.
> Am I doing something wrong? Do I have to use 0.4 for this to work?
> Help would be appreciated.
the soapCensus you're restoring does not have an _instance_key
attribute on it, so the merge() thinks its a pending instance (i.e.
has never been stored in the DB before), and adds it separately to
the session without affecting the current instance already in the
session. when the flush occurs, it conflicts with the existing
instance already in the session. so youd need to stick an
_instance_key on it before merging, which you can do via
soapCensus._instance_key = Session.identity_key(instance=soapCensus).
since people are starting to use merge() now, and consequently
tripping over its awkwardness, it seems like the method is going to
need more attention since I will grant that it probably should be
figuring out that the instance has a primary key on it already. i
added ticket 830 for this.
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