On 26 jan, 12:41, Adrian Bool <a...@logic.org.uk> wrote: > > I'm defining the DB in Python; using objects and inheritance. As such, when > I'm doing this I'm thinking in an object orientated (OO) manner - a service > uses a number of resources so I create a Service object with with either > foreign key or many-to-many (as appropriate) relationship to the Resource > objects. This gives me nice referential integrity and I can be sure that the > Service has valid connections to the Resources it requires. > > It seems, however, that Django expects the models not to be defined in an OO > manner. For example; should I wish resources to be listed as Inlines on the > Service's page I can only do this if the foreign key is with the Resource - > pointing 'up' the stack to the services - as possible to being pointed to by > the Service. Django seems to be defining stricture using an OO language; but > expecting that structure in a more traditional, relational database, style > where entries point up to their owners rather than the owners pointing down > to their children.
That's indeed how a relational DB works, and Django's ORM doesn't try to pretend the relational DB doesn't exists or is just a dumb 'bit bucket'. So, while models ares defined as classes, these are mostly - from this POV at least - "technical" objects wrapping the relational model, and not "pure" OO domain objects (whatever a "pure" OO domain object might be). This doesn't mean you have to go for an "anemic domain model" neither - your relational schema is part of the "domain space", and models (as well as managers) are also here to support additional responsabilitie. Some will talk about "OO/relational impedance mismatch" (ok, I cheated - Daniel just did;)), but I don't see it that way as far as I'm concerned - I'm using a relational model wrapped into an OO representation, and that's just what I want for most apps. -- 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. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
