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From: Wilt, Charles
Joe,
As I consider it, it seems to me that the owner end timestamp really isn't
derived from the start of the next owner timestamp.
Consider the question:
Who owned the car from 2/5/06@4:01 to 2/6/06@11:09?
I believe the derived answer would be Bill. But I think the correct
answer is nobody, given the original data.
However, if the OWNER table was chronologically complete as Chuck
suggested, then I agree with you that owner end timestamp would be
derivable.
With a non-complete OWNER table, you've got to get the owner end time from
someplace else.
As I see it, there's two options.
1) If the ownership period is separate from anything else, then you need
to store start & end.
2) If for instance, a particular transaction indicates start & end, then
you can derive both from the
transaction table.
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