On Aug 23, 2005, at 5:33 PM, Gary Stainburn wrote:
I want to create a courtesy car diary diary system where I have a
table
containing all of the cortesy cars in the pool, and then an allocation
table which has two timestamps, one for the start date/time and one
for
the return date/time.
How do I go about creating constraints on inserts and updates to
ensure
that
a) the finish is after the start
b) two allocations for a single vehicle don't overlap.
This is an interesting problem. You might want to take a look at this
book, previously mentioned on the one of the lists (by George Essig,
I believe):
Developing Time-Oriented Database Applications in SQL
by Richard T. Snodgrass
The book is out of print, but the author has made the PDF available
on his website at:
http://www.cs.arizona.edu/people/rts/tdbbook.pdf
Hope this helps!
Michael Glaesemann
grzm myrealbox com
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