It is because you are creating meeting object, before saving "place" in db. So place object doesn't have any id yet. So test 1 should be:
place = Place(where='Paris') place.save() meeting = Meeting(place=place, when='2011-01-01') meeting.save() return meeting 2011/8/19 Jacco <[email protected]> > I am having great difficulties in saving nested models in an easy > way. > > > Consider the following Example : > > ---------------------------------------------------------------------------------------------------------------------------------------------- > class Place(models.Model): > where = models.CharField(max_length=10) > class Meeting(models.Model): > place = models.ForeignKey(Place) > when = models.DateField() > > #Two (almost) identical functions: > def test1(): > place = Place(where='Paris') > meeting = Meeting(place=place, when='2011-01-01') > > place.save() > > meeting.save() > return meeting > > def test2(): > place = Place(where='Paris') > meeting = Meeting(place=place, when='2011-01-01') > > place.save() > meeting.place = meeting.place #BY setting meeting.place to > itself, it works !!!!!!!!!!!! > meeting.save() > return meeting > > ---------------------------------------------------------------------------------------------------------------------------------------------- > > > > - Running test1() results in crash "null value in column "place_id" > violates not-null constraint" > - Running test2() results in OK. > - Only difference is the dummy line "meting.place = meeting.place". > > Could someone who really understands this explain what is going on? > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To post to this group, send email to [email protected]. > 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. > > -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to [email protected]. 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.
