Hello Friends,

Please help me solve following situation in multiuser application.

I have a two date fields in one of my table in database.

Start date AND Stop Date.

Whenever I enter start date and stop date for new record. This start and stop should not overlap
with the dates of records which are already there in database.

for example, i have following entries in database.

start date stop date
06/14/99 06/20/99
06/22/99 06/25/99

now, for any new record , user can't enter start/stop date like 06/15/99 - 06/21/99 because it
overlaps the exsisting records.

That's why before saving any record, I check this validation by Select-sql on the database.This
works fine.

The problem is in multiuser situation. for example two users are entering new records at same time.
both have entered same start/stop date. let's say 06/27/99 - 06/30/99.

when User A goes to save this record, validation will check that is this range overlaps with any
previous records? He will not get any previous records with this range because User B has not
saved the changes yet. so He is allowed to save this record.

This is ok. but By the time User A gets the results of his query and he saves the record. User B saves the record.
so now, User A and User B both are allowed to save and database have duplicate entries.

I coudn't think what's the solution of this. I don't think I should user locking file mechanisam.

Please advise what's the solution of this situation.

Thanks in Advance

Thanks
Mark