This sounds like a case of "denormalization for performance," which is considered a bad idea by relational database experts; so are NULL fields. I think they are right, especially in a case like yours where your tables are so small and simple. Joining them is not a big deal, and data integrity will be easier to maintain.

Here is a site that may help: Database Debunkings

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

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