On Thu, 14 Jun 2007, Lza wrote:
> When I run a query on the policy table for a certain period, I also need
> to be able to pull the correct related rows (i.e. the information that
> would have been in the table at that time) from the tables linked to it.
Check out "Developing Time-Oriented Database Applications in SQL" by
Richard Snodgras; it's an entire book devoted to this and related topics.
It's out of print and hard to get, but you can download a free PDF copy
from the author at http://www.cs.arizona.edu/people/rts/publications.html
Much of the text shows how to simulate types and operations that now are
built-in to PostgreSQL, like the interval type, so it's not quite as
intimidating a read as it seems at first; there's a lot of code for older
databases that you can completely ignore.
--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD
