RE: Need ideas for SQL join select to replace logical view

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Joe Pluta
Sent: Sunday, September 16, 2007 9:57 AM
To: 'Midrange Systems Technical Discussion'
Subject: RE: Need ideas for SQL join select to replace logical view


You are suggesting storing the same information in two
records. Your end time of one event is the same as the start
time of the next event. That's by definition not normalized
data, and thus non-relational in nature.

Joe,

Not sure I agree with this.

There's a difference between storing the same data in two places, and storing two separate pieces of
data that happen to have the same value.

As I see it, start time and end time are two different pieces of information. In the OP's case, a
given start time happens to match a the prior records end time. I don't see that as violating
normalization rules.

Actually, given that BETWEEN is inclusive as you pointed out, I'd considering setting this up so that
the end time didn't match the next start time. Instead, the start time would be 1 mircosecond greater
than the last end time.


Charles


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