create table baseitems (
        id integer primary key,
        data text
);
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This table is the base for a bit of one-to-many inheritance for my second table:

create table items (
        id integer,
        subid integer,
        data text,
        primary key (id, subid),
        foreign key (id) references baseitems (id)
);
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I believe this structure is pretty self explanitory, and represents a simple inheritance type of relationship. So far, so good. The has_a and has_many relationships for this structure were easy to come up with. The problem I have comes in when I want to make a "third-level" table that references my "second-level" table 'items'. This third table is:

create table codes (
        id integer,
        subid integer,
        data text,
        unique (id, subid, data),
        foreign key (id, subid) references items(id, subid)
);
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I have no problem writing SQL to link all this stuff together in meaningful ways, and the approach seems valid... I haven't read much into database design, I sorta wing it, which may very well be my problem here.

I do have a problem explaining to Class::DBI that the foreign key that links a 'code' back to an item isn't a single column; the has_a method call only seems to accept a single column.. and I don't see any other way to establish this relationship with the interface provided.

I get the feeling that I've either overlooked pertinent information in the obvious places, or I haven't been looking in the right places at all. However, it's late for me, and I'm not too proud to ask for help. How do I make multiple column primary keys and foreign key references work with Class::DBI, or do I need to redesign my schema? Thank you...