Re: [HACKERS] Foreign keys: unexpected result from ALTER TABLE... ADD CONSTRAINT...

Peter Eisentraut wrote:
>On Mon, 17 Jan 2000, Oliver Elphick wrote:
>
>> I cannot do this pair of table creations directly, because they are mutual
>ly
>> dependent.
>>
>
>I don't think this will ever work. I can't really decode your intentions
>here but I recall that translating proper relational schemas (you know,
>the ones with the bubbles and lines) into tables never creates this sort
>of situation. Then again I could be wrong.

The idea is that suppliers of products can only supply products that are
purchased, rather than manufactured; and purchased products must have
suppliers. However, it is possible for there to be more than one potential
supplier of a product; the one listed in purchased_jobs is the currently
favoured supplier.

I guess I will have to remove the restriction that products listed in
product_suppliers must be purchased; it may indeed become possible for the
to change status from time to time, so that is not too unsatisfactory.

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
PGP key from public servers; key ID 32B8FAA1
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to give every man according as his work shall be."
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