Re: Why is MySQL more chosen over PostgreSQL?
От | Sander Steffann |
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Тема | Re: Why is MySQL more chosen over PostgreSQL? |
Дата | |
Msg-id | 003201c23b13$d3091380$64c8a8c0@balefire10ww обсуждение исходный текст |
Ответ на | Re: Why is MySQL more chosen over PostgreSQL? (Curt Sampson <cjs@cynic.net>) |
Ответы |
Re: Why is MySQL more chosen over PostgreSQL?
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Список | pgsql-hackers |
Hi, > > Well, if you also have soundcard_products, in your example you could have a > > product which is both a networkcard AND a soundcard. No way to restrict > > that a product can be only one 'subclass' at a time... If you can make that > > restriction using the relational model, you can do the same as with > > subclasses. But afaict that is very hard to do... > > CREATE VIEW networkcard_v AS SELECT * FROM products, networkcard WHERE > products.id = networkcard.prod_id; I think I was not clear enough... You just demonstrated that it is possible to have a card that is a soundcard and a networkcard at the same time. The point I tried to make was that it is difficult to _prevent_ this. Ofcourse I agree with you that your example fits the relational model perfectly! I have this problem in a few real-life cases, so if you have a sollution to this, I would realy appreciate it! Sander.
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