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Re: Why spurious tuples with fifth normal form?

From: <stowellt_at_gmail.com>
Date: 15 Jun 2005 15:19:50 -0700
Message-ID: <1118873990.646675.91420@g43g2000cwa.googlegroups.com>


Here is some more info:

The original table before I decomposed it was like this:

parameter_id // FK to a list of chemical parameters (silver, gold, etc.)
classification_id // FK to a list of classifications (drinking water, irrigation water, livestock
url_id // FK to a list of url links to web sites

I then decomposed the table into the following three relvars:

parameter_url
classification_url
parameter_classification

If I then re-join all three tables, I get spurious results. I am stumped as to the problem. did I decompse wrong? There is a complete many-to-many-to-many relationship between each of the three FK's. Any help is greatly appreciated. Received on Wed Jun 15 2005 - 17:19:50 CDT

Original text of this message

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