Re: diary constraints - Mailing list pgsql-sql
| From | Gnanavel S |
|---|---|
| Subject | Re: diary constraints |
| Date | |
| Msg-id | [email protected] Whole thread Raw |
| In response to | diary constraints (Gary Stainburn <[email protected]>) |
| List | pgsql-sql |
On 8/23/05, Gary Stainburn <[email protected]> wrote:
check constraint like -> "finish_time > start_time" this will do
Use "overlaps" function in a trigger to validate the above.
Hi folks
I know this has been discussed in the past, but no amount of keywords
has returned anything from the archives.
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
check constraint like -> "finish_time > start_time" this will do
b) two allocations for a single vehicle don't overlap.
Use "overlaps" function in a trigger to validate the above.
--
Gary Stainburn
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with regards,
S.Gnanavel
Satyam Computer Services Ltd.