Re: Do I need a PK on a join table?

Bob Badour wrote:

> SQL and DB2 confound the issue by mixing physical structures (indexes)
> with purely logical integrity constraints (uniqueness/keys), by allowing
> the abominable NULL,

I don't know where there is anything "mixed" and how NULL would fit into this statement. Could you possibly explain how you mean that?

> and possibly by limiting the declarable foreign key
> constraints to reference a single primary key per table.

This is not correct. In SQL, a FK can reference any unique constraint (incl. the primary key, of course).

> If you have a strong argument for wanting no index, declare a uniqueness
> constraint.

Which will be enforced by a unique index...

-- 
Knut Stolze
DB2 Information Integration Development
IBM Germany