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General question about CHECK constraints.

From: Paul <paul_at_see.my.sig.com>
Date: Wed, 21 Jun 2006 23:30:50 +0100
Message-ID: <v3ij92509h41venl219oh2j37nh2pndukv@4ax.com>

Hi all,

This is a general db design question that I have been pondering for a while.

If you have a field that is going to have a definite known number of values in advance i.e.

Gender(M, F, U), it's better to use a check constraint than have a gender table obviously.

My question is at what point does it become "better" to have a foreign key and not use a check constraint.

Month(Jan, Feb... Dec)?

LettersInAlphabet(A, B, C....Z)?

CountryCodes(AU, AS.... ZM)?

DayOfYear(1,2,3.... 366)?

WordsInSmallDictionary(Aardvark,..... Zygote)? Say 5000 entries?

TIA. Paul...

-- 

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Received on Wed Jun 21 2006 - 17:30:50 CDT

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