Re: Inheritance and foreign keys

On Tue, 9 Dec 2003, Brendan Jurd wrote:

> Hi all,
>
> I read on the manual page for Inheritance that:
>
> "A limitation of the inheritance feature is that indexes (including
> unique constraints) and foreign key constraints only apply to single
> tables, not to their inheritance children. Thus, in the above example,
> specifying that another table's column REFERENCES cities(name) would
> allow the other table to contain city names but not capital names. This
> deficiency will probably be fixed in some future release."
>
> I have a few projects that could benefit from inherited table structure,
> and it's a very cool idea, but this inability of indexes to include
> derived tables is a real functionality-killer. It's not "Object
> Relational" if the objects can't be related to anything!
>
> If someone could give me an idea of how far away this fix is, I'd be
> grateful.

I'd say at least 1, probably more versions out. Unique constraints across
an inheritance tree are pretty much a requirement for inherited foreign
keys and I'm not planning to even start thinking about the foreign key
side until after unique's done.

As a note, there are workarounds for foreign keys that have been mentioned
in the past. I'm not really sure anyone's post a real good workaround for
unique though.