Re: foreign key to the *same* table?

On Wed, 10 Sep 2003 00:05:46 +0200, Marco wrote:

> MySQL let me create the
> table and insert records, but problem begins with the clause ON DELETE SET
> NULL
        First, beware of MySQL -- it is not ISO SQL compliant, it has lotsa arbitrary restrictions. PostgreSQL is just as cheap, and much better.

        Second, think again... any solution involving NULLs is suspect. A nice, reationally sane solution to the hierarchy problem has been proposed by Fabian Pascal in his latest book, and it is a pearl of simplicity: simply a separate binary relation with the relationship between hierarchy nodes; for it, suffices two foreign keys to the main node relation.

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