On 9/6/05, asrenzo <[EMAIL PROTECTED]> wrote: > Here is my problem : > > Class Map(meta.Model): > name = meta.CharField(maxlength=255) > > Class City(meta.Model): > map = meta.ForeignKey(Map, null = True, blank = True) > name = meta.CharField(maxlength=255) > ... > [..] > If you wan't to delete the Map, all related Cities will be delete also. > It is great when a relation can not be null but you may want to keep > Cities' informations even if you delete a Map.
This concept is called referential integrity. http://en.wikipedia.org/wiki/Referential_integrity If you want to keep the Cities, edit them beforehand to set their Map to NULL. Note that there's a longstanding ticket for a "replace relationships" concept, which would allow an admin user to specify which value the deleted foreignkeys should be replaced with. See http://code.djangoproject.com/ticket/28 . Adrian -- Adrian Holovaty holovaty.com | djangoproject.com | chicagocrime.org
