On Fri, 2010-04-09 at 12:50 -0500, Kevin Grittner wrote: > I just thought that if you were adding more type information, > oriented aournd the types themselves rather than index AMs, some form > of inheritence might fit in gracefully.
There are already some specific proposals for inheritance in database theory literature. For instance: "Databases, Types, and the Relational Model" by C.J. Date addresses inheritance explicitly (and the appendices have some interesting discussion). I'm not sure how compatible it is with SQL, though; and I am not very optimistic that we could accomplish such a restructuring of the type system while maintaining a reasonable level of backwards compatibility. Either way, I think it's a separate topic. Two types that are not related by any subtype/supertype relationship (like strings and ints) can conform to the same interface (total ordering); while the very same type can conform to two different interfaces. Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers