I've considered the address-type-and-foreign-key approach you describe — and implemented it and then backed it out again — but that approach bugs me at a philosophical level. Address is then bound explicitly to Producer and instead of having two addresses each with a specific designation I can have 0-n addresses, one producer with 14 physical addresses, and so on. I understand that I can guard against these situations through validation and overriding save methods and such but object composition seems like such a simple, common, basic need I'm stunned to find it's not easily achievable.
Thanks for the input. On Wednesday, February 13, 2013 2:59:56 PM UTC-6, Adam Mesha wrote: > > Inlines are for related objects, meaning when I have a foreign key from A > to B, on A there is an actual database field that points to B, but on B > there's a virtual (related object) field implemented as a python method. > When you have a foreign key, the way the admin shows that is just to give > you a drop-down list so you can choose the corresponding object in the > other model. > > To go back to the standard example, there is a foreign key pointing from > Book to Author. On the Author admin page you can see and edit all the > books, but on the Book page you just have a drop-down to select the > relevant author. You could think of it as Book extends in a certain sense > Author, so it has a field pointing to its parent. > > What I would probably do in your situation is to get rid of the mailing > address and physical address in your Producer model, and add a type > field(which could be 'mailing' or 'physical' or maybe some more > possibilities) and a producer field foreign key. That would allow for > easily adding more types of addresses, and more than one of a given type. > If it's essential to guarantee that there is exactly one mailing address > and exactly one physical address, I would probably override the relevant > save methods to check for that when objects are saved. > > On Wed, Feb 13, 2013 at 9:25 PM, Ray Hatfield > <ray.ha...@gmail.com<javascript:> > > wrote: > >> Hi, >> >> I have a model which requires two addresses: a mailing address and a >> physical address. From an OO perspective it makes sense to have an Address >> class and the Producer to have Address instances as properties, but I can't >> seem to achieve this in django while still being able to edit the addresses >> inline as part of the Producer admin. >> >> I've tried this sort of thing: >> >> class Address( models.Model ): >> street = models.CharField( ... ) >> # city state zip, etc. >> >> class Producer( models.Model ): >> mailing_address = models.OneToOneField( Address, related_name='+' ) >> physical_address = models.OneToOneField( Address, related_name='+' ) >> >> but when I attempt to inline the addresses in the django admin I run into >> trouble. I get errors like: >> >> <class 'producers.models.Address'> has no ForeignKey to <class >> 'producers.models.Producer'> >> >> (This error is true, of course. But I was under the apparently erroneous >> impression that including related_name='+' would prevent django from >> setting up the reverse relationship.) >> >> I realize I could add a foreign key to Address to associate it with a >> specific Producer but this feels backwards to me. An Address shouldn't need >> to know whether it's for a Producer or some other object. It's just an >> address. >> >> I've been banging my head on this for far too long. Advice? >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Django users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to django-users...@googlegroups.com <javascript:>. >> To post to this group, send email to django...@googlegroups.com<javascript:> >> . >> Visit this group at http://groups.google.com/group/django-users?hl=en. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > > > -- > Adam Mesha <ad...@mesha.org <javascript:>> > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at http://groups.google.com/group/django-users?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
