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04/01/1999 07:58:16
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Titre:
Divers
Thread ID:
00171828
Message ID:
00172423
Vues:
31
>I would disagree with that. Just adding a new PK field to a record which already had a multifield PK doesn't remove the necessity for normalization. The problems involved with 4NF (I wouldn't worry too much about 5NF; it's quite unlikely to pop up) don't get solved by adding more PK's to a table.

Fredreico,

4th normal form states that the primary key composed of more than one attribute will not have independently multivalued components of the primary key. Therefore if the pk is a single field the 4th normal form does not apply. 4th normal form speaks nothing about other candidate keys, only the primary key and any table has only one primary key. 5th normal form also speaks only about the primary key of three or more component attributes.
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