I think a few posts back in this thread there were links to a great book
by Richard Snodgrass on the subject . It details how this is often
implemented by disallowing any updates to any records' fields except to
the *end_date* timestamp field. All updates to regular fields turn into
inserts, with the start_date and end_date fields determining at which
moment in time the record was valid.
An update turns into a two part transaction(simplified, but not much):
update table set end_date = now() where now() between start_date and
end_date;
insert into table(x,x,x, start_date, end_date) values (x,x,x, now()+1,
'2999-01-01');
Then all queries take into account the timestamps, by adding clauses
like "and now() between start_date and end_date".
I do not want to discount the amount of work it would take to roll this
into the OpenERP ORM, but it should definitely be considered.
I'd love to free up some time to help work on this.
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