As long as two users are using the form at the same time and both try to add the same user i.d.. The second person to add the user i.d. will have a problem with the primary key.

Joe

>I gather that this is a "add user" form?
>if so in the init of the form or the gotfocus of the textbox I would do
>
>Select DISTINCT user_id ;
>from blabla ;
>into array a_user_id
>
>then in the lostfocus or valid of the textbox I would do
>
>ln_ret = ASCAN(a_user_id, this.value)
>if ln_ret <> 0
>return .t.
>else
>messagebox('error',0,'error')
>return .f.
>endif
>
>I think you get the jist of it
>
>Stephen McLaughlin
>"Blastmaster"
>stephenmclaughlin@email.com