Hey Carlos,

Consider changing the machine ID from being a user input to a programmed entry using SYS(0). If you can't do that, surely you can use old-fashioned locking to lock the base table on Save and do a query for entires for that machine for conflicting time period as Alex mentioned?




>Hello.
>
>I have users that input these data into a form at the same time:
>
> Machine Start Time End Time
>user 1 01 1430 1545
>user 2 02 1500 1630
>user 3 01 1600 1648
>etc.
>
>If by mistake user 2 inputs Machine 01 (it's already working)
>
>How do I prevent that data from being stored using the insert sentence ?
>There is no primary key to compare user's input.
>
>Thank you.
>
>c.x.