On Feb 10, 2010, at 8:36 AM, Kent wrote: >> I've researched this in the past and they don't. I will look into >> re-introducing "allow_null_pks" as a new flag "allow_partial_pks", >> defaults to True, will be honored by merge(), you set yours to False. >> this is 0.6 only. >> > > Thanks for your consideration, it seems that would be beneficial for > us. As a side note, though, if no databases allow this, why would we > default to True instead of False?
because people map to outerjoins (often). then you get a partial PK. > > Does allow_partial_pks have additional meaning, such as "complain if > the object only has part of the primary key set?" not allowing partial pks means dont consider (2, None) to be a primary key - its treated like "None". > > You mentioned the main thing was how this affects outer joins. Can > you expand on how this might cause outer joins to return no rows? Is > it because users still expected a row returned from the *other* > tables, even though part of this key is null? > (I don't want to make you go back through the effort of re-adding this > flag if it might cause me unanticipated side-effects that force me to > abandon it, so maybe pointing me to an example of the main complaint > when setting it to False? I'd like attempt to rule out that it might > affect me.) yes, an outerjoin can return a row for table A but NULL for table B. its totally fine, we have flipped the defaults in 0.6 and we'd just be making the "other" behavior available again. > > Thanks > > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To post to this group, send email to sqlalch...@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 sqlalch...@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.
