Thank you, Michael, but I need to use multi-table rather than abstract inheritance in this instance, as the Place model already exists as a concrete model, and I'm adding the Restaurant model. Also, for database design reasons, I'd prefer to keep the tables separate.
On Nov 6, 9:02 pm, Michael Sprayberry <michaelspraybe...@yahoo.com> wrote: > Hello, > > I was just going through this posting and I noticed that you are using > concrete inheritance in your calling of > > class Place(models.Model): > name = models.CharField(max_length=50) > address = models.CharField(max_length=80) > > class Restaurant(Place): > place = models.OneToOneField(Place, parent_link=True, > related_name='restaurant') > serves_hot_dogs = models.BooleanField() > serves_pizza = models.BooleanField() > > Try > > class Place(models.Model): > name = models.CharField(max_length=50) > address = models.CharField(max_length=80) > > class Meta: > abstract = True > > class Restaurant(Place): > place = models.OneToOneField(Place, parent_link=True, > related_name='restaurant') > serves_hot_dogs = models.BooleanField() > serves_pizza = models.BooleanField() > > > This is abstract inheritance and any model inheriting Place will get a copy > of Place's fields onto the child object instead of getting another Table > placed there. > > Michael > > --- On Sat, 11/6/10, ringemup <ringe...@gmail.com> wrote: > > From: ringemup <ringe...@gmail.com> > Subject: Re: Multi-table Inheritance: How to add child to parent model? > To: "Django users" <django-users@googlegroups.com> > Date: Saturday, November 6, 2010, 7:48 PM > > That documentation is for pre-1.0 versions of Django, when model > inheritance wasn't available at all. Multi-table inheritance doesn't > seem to work identically to plain one-to-one relations. > > On Nov 6, 3:47 pm, Derek <gamesb...@gmail.com> wrote: > > > > > See:http://www.djangoproject.com/documentation/models/one_to_one/ > > > On 6 November 2010 14:47, ringemup <ringe...@gmail.com> wrote: > > > > I can't find that example in this documentation [1]. Is there other > > > documentation that I'm not aware of? > > > > [1] > > >http://docs.djangoproject.com/en/dev/topics/db/models/#multi-table-in... > > > > On Nov 6, 5:59 am, Derek <gamesb...@gmail.com> wrote: > > > > The example shown in the online documentation. > > > > > On 5 November 2010 18:24, ringemup <ringe...@gmail.com> wrote: > > > > > > **{} is sort of the inverse of **kwargs in a function signature -- > > > > > it's a way to use a dictionary in place of keyword arguments, and > > > > > should function identically. > > > > > > Which "original example" are you referring to? > > > > > > On Nov 5, 10:25 am, Derek <gamesb...@gmail.com> wrote: > > > > > > You mean "trying to add a Restaurant which is linked to an existing > > > > > place" > > > > > > > I am not familar with the syntax you are using for the **{} wrapper. > > > > > > > The original example shows: > > > > > > > r = Restaurant(place=p1, serves_hot_dogs=True, serves_pizza=False) > > > > > > > and the attached note says: > > > > > > > Pass the ID of the "parent" object as this object's ID. > > > > > > > Are you sure that the place ID is, in fact, what is being > > > transferred? > > > > > > > On 5 November 2010 15:59, ringemup <ringe...@gmail.com> wrote: > > > > > > > > I'm not trying to create a Restaurant without a name and address. > > > I'm > > > > > > > trying to turn an existing Place into a Restaurant. > > > > > > > > On Nov 5, 9:42 am, derek <gamesb...@gmail.com> wrote: > > > > > > > > Its not clear exactly what you think the problem is. The system > > > is > > > > > > > > behaving correctly ito the way you have set it up. > > > > > > > > > 1. You have specified that name and address are compulsory > > > > > > > > fields > > > in > > > > > > > > Place. > > > > > > > > 2. You have specifed that Restaurant must be linked to Place > > > (i.e. > > > > > > > > Place must be created before Restaurant can be created) > > > > > > > > > So why would you now want an entry in Restaurant that does _not_ > > > have > > > > > > > > a name and address? > > > > > > > > > On Nov 4, 10:25 pm, ringemup <ringe...@gmail.com> wrote: > > > > > > > > > > I have an existing model that I want to extend using > > > multi-table > > > > > > > > > inheritance. I need to create a child instance for each > > > > > > > > > parent > > > > > > > > > instance in the database, but I can't figure out how. I've > > > scoured > > > > > > > > > google and haven't come up with anything other than Ticket > > > > > #7623[1]. > > > > > > > > > Here are some of the things I've tried... > > > > > > > > > > Let's adapt the Place / Restaurant example from the docs: > > > > > > > > > > class Place(models.Model): > > > > > > > > > name = models.CharField(max_length=50) > > > > > > > > > address = models.CharField(max_length=80) > > > > > > > > > > class Restaurant(Place): > > > > > > > > > place = models.OneToOneField(Place, parent_link=True, > > > > > > > > > related_name='restaurant') > > > > > > > > > serves_hot_dogs = models.BooleanField() > > > > > > > > > serves_pizza = models.BooleanField() > > > > > > > > > > I want to do the following, in essence: > > > > > > > > > > for place in Place.objects.all(): > > > > > > > > > restaurant = Restaurant(**{ > > > > > > > > > 'place': place, > > > > > > > > > 'serves_hot_dogs': False, > > > > > > > > > 'serves_pizza': True, > > > > > > > > > }) > > > > > > > > > restaurant.save() > > > > > > > > > > Of course, doing this tries to also create a new Place > > > belonging to > > > > > > > > > the new Restaurant, and throws an error because no values have > > > been > > > > > > > > > specified for the name and address fields. I've also tried: > > > > > > > > > > for place in Place.objects.all(): > > > > > > > > > restaurant = Restaurant(**{ > > > > > > > > > 'serves_hot_dogs': False, > > > > > > > > > 'serves_pizza': True, > > > > > > > > > }) > > > > > > > > > place.restaurant = restaurant > > > > > > > > > place.save() > > > > > > > > > > This, however, doesn't create any records in the restaurant > > > table. > > > > > > > > > > Any suggestions? > > > > > > > > > > [1]http://code.djangoproject.com/ticket/7623 > > > > > > > > -- > > > > > > > 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<django-users%2bunsubscr...@googlegroups.com> > > > <django-users%2bunsubscr...@googlegroups.com<django-users%252bunsubscr...@googlegroups.com> > > > > > > <django-users%2bunsubscr...@googlegroups.com<django-users%252bunsubscr...@googlegroups.com> > > > <django-users%252bunsubscr...@googlegroups.com<django-users%25252bunsubscr...@googlegroups.com> > > > > > > > > . > > > > > > > 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 django-us...@googlegroups.com. > > > > > To unsubscribe from this group, send email to > > > > > django-users+unsubscr...@googlegroups.com<django-users%2bunsubscr...@googlegroups.com> > > > <django-users%2bunsubscr...@googlegroups.com<django-users%252bunsubscr...@googlegroups.com> > > > > > > . > > > > > 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 django-us...@googlegroups.com. > > > To unsubscribe from this group, send email to > > > django-users+unsubscr...@googlegroups.com<django-users%2bunsubscr...@googlegroups.com> > > > . > > > 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 django-us...@googlegroups.com. > To unsubscribe from this group, send email to > django-users+unsubscr...@googlegroups.com. > For more options, visit this group > athttp://groups.google.com/group/django-users?hl=en. -- You received this message because you are subscribed to the Google Groups "Django users" group. 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