Re: Database theory (was Re: one-to-one)

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: Ron Johnson <ron(dot)l(dot)johnson(at)cox(dot)net>
Cc: pgsql-novice(at)postgresql(dot)org
Subject: Re: Database theory (was Re: one-to-one)
Date: 2003-08-22 01:21:39
Message-ID: 200308211821.39106.josh@agliodbs.com
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Ron,

> God bless you, Tiny Tim! I had a similar discussion on [general]
> last week regarding arrays.

<grin> sure. Although arrays can be atomic and thus properly relational; it
just depends on how they are used. Examples:

array of ordered molicules making up a genome: atomic & relational

array of points making up a graph: atomic & relational

array of languages spoken by a salesperson: non-atomic, non-relational

array of products offered by a supplier: non-atomic, non-relational

The real question to ask oneself when using an array data type is: "is the
data I am representing an ordered set which does not have meaning as
individual elements, and does not have the same meaning in a different
order?" If the answer is yes, then please use an array. If the answer is
no, then you should be using a related "child" table instead.

--
-Josh Berkus
Aglio Database Solutions
San Francisco

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