Thank you very much On Tue, Oct 25, 2011 at 3:46 PM, Michael Bayer <mike...@zzzcomputing.com>wrote:
> you can use a "dynamic" relationship which allows you to say: > > some_parent.items.order_by(items.c.id.desc()) > > > http://www.sqlalchemy.org/docs/orm/collections.html#dynamic-relationship-loaders > > > On Oct 25, 2011, at 5:02 AM, neurino wrote: > > > I need to change a collection order_by when a parent instance mapped > > attribute changes. > > > > Something like this: > > > > parents = Table('parents', metadata, > > Column('id', Integer, primary_key=True) > > Column('reverse', Boolean, primary_key=True) > > ) > > items = Table('items', metadata, > > Column('id', Integer, primary_key=True) > > ) > > .... > > mapper(parents, Parent, > > properties={ > > 'items': relationship(Item, > > backref='parent', > > collection_class=ItemsList, > > order_by=items.c.id > > ) > > } > > > >>>> parent = session.query(Parent).first() > >>>> parent.reverse > > False > >>>> parent.items > > [<Item 1>, <Item 2>, <Item 3>] > >>>> parent.reverse = True > >>>> parent.items > > [<Item 3>, <Item 2>, <Item 1>] > > > > I already use a custom collection and I could make custom __iter__ > > according to first item (if any) `self.parent.reverse` but it seems to > > me a bit too tricky. > > > > Any advice? > > > > Thank you for your support > > > > -- > > 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. > > > > -- > 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. > > -- 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.
