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From: rlh@fciva.FRANKLIN.COM (Ramon L. Holt)
Newsgroups: comp.databases
Subject: Re: A few words on the "normaliztion"
Summary: Please explain 3NF and 4NF
Message-ID: <489@fciva.FRANKLIN.COM>
Date: 3 Aug 89 18:46:30 GMT
References: <36270004@hpindwa.HP.COM> <36270005@hpindwa.HP.COM>
Reply-To: rlh@fciva.UUCP (Ramon L. Holt)
Organization: Franklin Capital Investments, Inc. McLean, Va.
Lines: 23

In reply from <marti@ethz.UUCP>, marti%inf.ethz.ch@relay.cs.net (Robert Marti) 
wrote :
>
> No DBMS enforces 4NF (or "multi-valued update consistency", as you call
> it).  The database designer enforces 4NF, essentially by defining a
> table per MVD.  Note that this is no differnet from 3NF:  The designer
> enforces 3NF by defining appropriate tables and keys.

I have been following along this line of discussion and understand most of
it and have even learned something new (like that keeping similar data in 
as few places as possible in called normalization) but could someone explain 
3NF, 4NF and MVD ? Could you also provide some simple examples that would
show the differences between these levels of normalization (they are levels 
dealing with normalization aren't they?).

Thank you.

Rame.

-- 
Ramon L. Holt				Franklin Mortgage Capital Corp.
(703) 448-3300				7900 Westpark Drive, Suite A-130
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