Hi!
>
> And if that name already exists there would be a duplicate key error.
Name cannot exist: First delete deletes its value. Tables are not
changed by external process during transaction. As double insurance,
insert perfoms additional existence check and adds only if key does not
exist.
>Last inserted row data should remain.
>
> I'm not understanding the above.
This table should contain last login time, user and ip address. It
should be updated by every process on login. For this old entry is
removed if it exists and new entry with same primary key is added.
Andrus.