On 12/11/2015 05:25 PM, Gerald Thibault wrote: > I am basing my question off the code > at > http://docs.sqlalchemy.org/en/latest/orm/relationship_persistence.html#rows-that-point-to-themselves-mutually-dependent-rows, > with a few changes. > > I am trying to handle a situation very similar to the one in that > example, with 2 classes having the same relationship types as those in > the example. However, I would like to create the instances without using > the relationships, and instead populate the fk values directly. The > example uses this, and it works. > > w1 = Widget(name='somewidget') > e1 = Entry(name='someentry') > w1.favorite_entry = e1 > w1.entries = [e1] > session.add_all([w1, e1]) > session.commit() > > I would like to do this: > > w1 = Widget(widget_id=1, favorite_entry_id=1, name='somewidget') > e1 = Entry(entry_id=1, widget_id=1, name='someentry') > session.add_all([w1, e1]) > session.commit() > > The reason I am doing it this way is because I am operating from a JSON > fixture file, and trying to populate a database for unit testing. The > method used in the example works perfectly, but trying to do it my way > yields: > > sqlalchemy.exc.IntegrityError: (IntegrityError) (1452, 'Cannot add or > update a child row: a foreign key constraint fails (`test`.`widget`, > CONSTRAINT `fk_favorite_entry` FOREIGN KEY (`favorite_entry_id`) > REFERENCES `entry` (`entry_id`))') 'INSERT INTO widget (widget_id, > favorite_entry_id, name) VALUES (%s, %s, %s)' (1, 1, 'somewidget') > > I understand the post_update option is on the relationship, and not the > column, so it has no effect on column population. Is there an > alternative method to have that column populated separately via a second > statement, similar to the post_update functionality?
Sure, you have to do it manually: w1 = Widget(widget_id=1, favorite_entry_id=None, name='somewidget') e1 = Entry(entry_id=1, widget_id=1, name='someentry') session.add_all([w1, e1]) session.flush() # optional if you're on autoflush session.query(Widget).filter_by(widget_id=1).update(favorite_entry_id=1) session.commit() > > -- > 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 http://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. 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/d/optout.
