On May 30, 2009, at 1:56 AM, ericthompso...@gmail.com wrote:
> Upon reaching the instantiation of Foo, my code blows up with the > error message in the subject. Now I realize this is often caused by > threading issues - multiple threads, each with their own Session, > trying to touch an entity without first merging that entity into the > thread's local session. But my application is single-threaded and to > the best of my knowledge I'm not creating any new sessions other than > the ScopedSession that was created when I imported elixir. Even if I > had attempted to create several sessions via elixir_session(), my > understanding is that I would have been returned the same session > because I haven't changed threads and elixir by default uses a > ScopedSession. that is all correct. > So why is Foo winding up in a new session (and how did > it already get attached to my current session)? I haven't passed any > options regarding the session in my entity definitions. I can't see anything here which would cause this. A frequent cause of this confusion is when a library makes use of the ScopedSession.mapper method which has the effect of objects being automatically added to a session without the need to say session.add(object) - but again confusion would only occur here if there is more han one session in use. > On a somewhat related note, why does Session have so many class > methods? It's perplexing to me that I can do things like > elixir_session.query(Foo).all() and also elixir_session().query > (Foo).all(). I've tried digging through Elixir's entity.py and > SQLAlchemy's session.py but I didn't get much out of my first couple > of reads. its the ScopedSession you're dealing with. The methods are not class methods, as ScopedSession is instantiated. for every public Session method, the ScopedSession implements a proxying method which will invoke that method upon a Session pulled from a threading.local() object. To access the Session stored in the threading.local() directly, ScopedSession implements __call__(). --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
