mviamari wrote: > > Hello, > > I'm writing tests for my database, and I've run into a little bit of > confusion. > > Say I have a class (we'll call it person) with two declared attributes > that correspond to db columns: > > person.id > person.name > > If I randomly assign a person object another attribute dynamically: > > person.undeclared_value = 'New' > > That value doesn't get stored in the database. (That part I expected > and understand). > What I don't understand is if I commit the object, set it to None (to > presumably garbage collect it) and then reacquire it from the DB, > sometimes that dynamically declared attribute is still pesent: > > person = Person() > person.name = 'John Smith' > person.new_attr = 'New' > > commit() > id = person.id #id isn't assigned till after a commit > > person = None > person = Person.get_by(id=id) > > #This is expected to be true > assert person.name = 'John Smith' > > #This is expected to yield an AttributeError, but sometimes it doesn't > assert person.new_attr = 'New' > > Based on my tests, it appears that the sometimes it doesn't is > whenever there are relationships created in the session. If I only > create one object and follow the above pattern, I get the expected > results. If I create two objects and the relationship between them, > then I get the unexpected results. > > Does anyone have any idea what might be going on? I think the object > is getting stored in the session, and when I reobtain the object it > just uses the reference in the session.
this is the identity map at work. Read "Is the session a cache?" at http://www.sqlalchemy.org/docs/05/session.html#frequently-asked-questions . --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
