[Dbix-class] Schema design query

[Ovid]

----- Original Message ----

> From: Dermot <paikkos at googlemail.com>

> > Yes, you are missing something. UNIQUE( x, y ) means that the
> > combination of X and Y must be unique. It's a mutli-column constraint.
> > So, you couldn't have two rows with cd_id=1, genre_id=2. But, your
> > example list would be just fine.
> 
> Thanx Rob I didn't realise that UNIQUE could bound over multiple
> columns like that.

In fact, assuming you're working with a properly normalized database, almost every table should be considered in practice (if not in reality) to have a unique constraint over all columns (aside from the ID) where the values are truly identifying.  (There's one counter-example I can think of, but in practice, I've never seen it).

 
Cheers,
Ovid
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