On 02/16/2016 11:42 AM, Michael Naber wrote:
That's interesting. So, if I'm trying to move instances between threads, is it recommended that I pass between threads the instance id, and then in the receiving thread use session.query(Person).get(instance_id), or... should I pass the instance itself (not by ID), and then use session.merge(instance)? My objective is that I would want to have full access to access and modify the instance in the session of the receiving thread.
you can pass the full instance from one thread to another, and have the receiving thread merge() it into the receiving session. the only thing you need to watch for in this case is that the receiving thread is now going to be handling the object you give it in a read-only sense, but if that object is still associated with the originating thread's Session then you're going to have thread-concurrent access to that session, which is dangerous. So you can either synchronize the threads on the point at which the receiving thread is calling merge() or you can detach the object from the Session before giving it to the receiving thread.
Thank you, Michael On Tue, Feb 16, 2016 at 11:26 AM, Mike Bayer <clas...@zzzcomputing.com <mailto:clas...@zzzcomputing.com>> wrote: answered On 02/16/2016 09:08 AM, Michael Naber wrote: I would like to write code which can correctly merge objects of type X or any subclass of type X into the session. I have been doing session.merge(X(id=??)), which works fine for merging type X, but if the object ID references an instance of any subclass of X, the merge results in the discriminator being set incorrectly. Code example here: http://stackoverflow.com/questions/35414057 Any help much appreciated. Regards, Michael -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com <mailto:sqlalchemy%2bunsubscr...@googlegroups.com> <mailto:sqlalchemy+unsubscr...@googlegroups.com <mailto:sqlalchemy%2bunsubscr...@googlegroups.com>>. To post to this group, send email to sqlalchemy@googlegroups.com <mailto:sqlalchemy@googlegroups.com> <mailto:sqlalchemy@googlegroups.com <mailto:sqlalchemy@googlegroups.com>>. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com <mailto:sqlalchemy%2bunsubscr...@googlegroups.com>. To post to this group, send email to sqlalchemy@googlegroups.com <mailto:sqlalchemy@googlegroups.com>. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com <mailto:sqlalchemy+unsubscr...@googlegroups.com>. To post to this group, send email to sqlalchemy@googlegroups.com <mailto:sqlalchemy@googlegroups.com>. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
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