On Mon, 2007-11-19 at 17:19 -0300, Alvaro Herrera wrote: > Kynn Jones escribió: > > I have two classes of objects, A and B, where B is just a special case > > of A. (I.e., to describe a B-type object I need to specify the same > > fields as for an A-type object, plus a whole bunch additional fields > > specific to B alone.) Furthermore, there's a third class T that is in > > a many-to-one relation with A (and hence also B) objects. > > > > The question is, what's the "best practice" for implementing this > > situation in PostgreSQL. My first idea was to define B as inheriting > > from A, which is OK, except that I have not figured out how to > > implement the reference from T. Is inheritance indeed the right tool > > for this problem, or should I use a different approach? > > It would be the right tool if the FKs worked :-( Sadly, they don't. > I don't think it's that bad of a situation. It would be great if PostgreSQL did support keys across tables, but it's not necessary for a good design in his case. The difference between using inheritance and just using multiple tables (like the alternative that I suggested) is the difference between vertically partitioning and horizontally partitioning. Both seem like good choices to me. Regards, Jeff Davis ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
