If you use PostgreSQL, you can declare the derived table types as truly derived. Then a query against the parent type by default does an implicit join over all subtypes (unless you add an ONLY keyword). It's pretty slick.

If you have a choice of databases, choose PostgreSQL. Particularly if you are using something like MySQL only out of inertia.

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

In reply to •Re: SQL Joins across Subclasses by merlyn
in thread SQL Joins across Subclasses by djantzen

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