On Tue, 2008-07-01 at 23:10 -0400, Wanrong Lin wrote: > Hi, > > This topic has been discussed before here: > http://groups.google.com/group/django-users/browse_thread/thread/fcd04f766b101a95/b65b70aa6b03729e?lnk=gst&q=unique_together%2C+null# > > Don't you agree that two field combinations like ("A", null) and ("A", > null) should be considered identical and hence should be blocked from > being entered into the database when "unique_together" condition is > imposed on that field combination? Right now Django does not think so > and will let both of those two records get into the database, which is > really puzzling to me. Any rationale for such a counter-intuitive (to > me) behavior?
In SQL, all NULLs are unique (NULL != NULL). So this isn't counter-intuitive at the SQL level and unique_together is enforced at that level. I guess the solution is not to allow NULLs in those fields if you can avoid it, or manually add a more complex check constraint to the database table (exact syntax and format will depend upon your database). Malcolm --~--~---------~--~----~------------~-------~--~----~ 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 [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
