Re: "REFERENCES" and UNIQUE

On Wed, 4 Jan 2006, Stephan Szabo wrote:

> Which in this case hints that there's a problem with the schema.
>
> What is the final effect you're looking for?  The above does let you

Err, that should be doesn't.

> lookup the DE or FR strings for a city of a member (what if two cities had
> the same EN name but different DE or FR names, how would you decide which
> one it was). If you only wanted to make sure that the city name was in a
> list, then it wouldn't matter if you made it unique.
>
> > Is there a solution for this problem?
>
> The easiest is to write triggers that check for a matching row on insert
> or update to members and make sure that you aren't removing the last match
> on update or deletion of cities. You need to be a little careful to get
> the locking right for concurrent actions on cities and members.
>
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