Hi Michael, since i might also start with a Role instance and add User instances to them i need a symmetrical solution with regard ref and backref (and i think casade_backrefs=False would not work in that case?).
So i tested two solutions which both seem to work in this specific case: - create a separate session for the query on Role (session.query(Role).all()); not the same session the User instance is in (as i did before) - set autoflush to false on the query as in (session.query(Role).autoflush(False).all()) Since you did not mention the second solution, i wondered whether there are possible disadvantages to the second approach; the first one seems slower but cleaner. Cheers, Lars On Wed, Nov 20, 2013 at 4:51 PM, Michael Bayer <mike...@zzzcomputing.com>wrote: > you either want to prevent User from being cascaded and/or added into the > Session ahead of time, which if this is occurring via backref you might > want to look at casade_backrefs=False ( > http://docs.sqlalchemy.org/en/rel_0_9/orm/session.html?highlight=cascade_backrefs#controlling-cascade-on-backrefs). > If not that, then use “with session.no_autoflush” for the period of > time that you query for Role. > > > > > On Nov 20, 2013, at 8:02 AM, lars van gemerden <l...@rational-it.com> > wrote: > > Hi all, > > I have 2 sqla classes with mapped tables: User and Role with a many to > many relationship (User.roles/Role.users) through an association table. > User has columns email and password, both non nullable. > > I create an instance of User but do not commit it yet, next i do a query > on Role: session.query(Role).all() (to be able to let an end-user choose > one or more roles for the for the newly created User). > > This gives the error: IntegrityError: (IntegrityError) User.email may not > be NULL u'INSERT INTO "User" (_created_, discriminator, email, password) > VALUES (CURRENT_TIMESTAMP, ?, ?, ?)' (None, None, None) > > I think the query tries to flush the instance of User, which causes the > error. > > My questions is: Why and how do i avoid it? I just want a list of all > roles currently in the Role table to be able to assign one or moe to the > User instance. > > Cheers, Lars > > > > -- > 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. > > To post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at http://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- ==================================== Lars van Gemerden l...@rational-it.com +31 6 26 88 55 39 ==================================== -- 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. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/groups/opt_out.
