Thank you for the explanation. Seems to be the correct solution of the problem (NULL, v1) != (NULL, v1) is overwrite the save method and check for existence of (NULL, v1) before saving a new instance of (NULL, v1). What I don't understand, why are the well-known databases so stupid and why they can't do this job. What about make this pre- save chceck as statndard behavior in Django?
On 11. Aug, 16:57 h., Karen Tracey <kmtra...@gmail.com> wrote: > On Tue, Aug 11, 2009 at 10:40 AM, Alex Gaynor <alex.gay...@gmail.com> wrote: > > > On Tue, Aug 11, 2009 at 8:25 AM, gentlestone<tibor.b...@hotmail.com> > > wrote: > > > > On 11. Aug, 15:01 h., Gustavo Henrique <gustavo...@gmail.com> wrote: > > >> Try also: null=True, blank=True > > > >> -- > > >> Gustavo Henriquehttp://www.gustavohenrique.nethttp:// > > blog.gustavohenrique.net > > > > blank=True ... I have had, but this one doesn't solve the problem, > > > maybe the problem is in postgresql, the associated SQL code for > > > postgresql is > > > > CREATE TABLE ... > > > ... > > > UNIQUE ("some_fk_field_id", "some_plain_field"), > > > > and this apparently doesn't work > > > You are talking about in the forms/admin validation correct? Thinking > > to how this is implemented there likely is a bug where this doesn't > > use the SQL concept of NULL != NULL and uses the Python None == None > > instead, which of these behaviors is correct I'm not sure of (though I > > lean towards the SQL interpretation). > > I don't believe there is a bug. The original description of the problem > confused me because I thought it was trying so specify unique_together for a > field in one model and a field in another model related by a nullable > foreign key, and I didn't think you could do that. In fact you can't -- all > the fields have to be in the same model/table and I see now that the > original report wasn't saying that. (The _field in the unique_together spec > is what confused me as I read that as having a double underscore.) > > Anyway, form validation allows multiple allows multiple None/NULL values > here since most of the database backends interpret NULL != NULL at the SQL > level to mean that (NULL, v1) != (NULL, v1) when doing multiple field unique > checks. The one exception I know of is Oracle, it apparently will raise an > IntegrityError for this case. See the discussion here: > > http://code.djangoproject.com/ticket/9039#comment:10 > > Karen --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
