Delete allowed in a multirow blk only if no records exist in another table

Question

How can I delete an existing row in a multirow block after checking that no records exist in another table ?
How do I proceed please ?
I know I need to check the primary keys of both tables to do that . Please help.

Answer 1

I've written the following code in the KEY-DELREC trigger :
DECLARE
*     Fail EXCEPTION;*
*     alert_title varchar2(100) := null;*
*     p_button_choice number := 0; -- 10g : for Stop_Alert, Caution_Alert & Note_Alert*
*     cnt NUMBER;*
*     choice NUMBER;*
Begin
*     If :system.record_status NOT IN ('INSERT', 'NEW') THEN -- can be CHANGED or QUERY mode*
*          begin*
*          SELECT count(AMD_CODE)*
*          INTO cnt*
*          FROM t_mmamd,t_amdtype*
*          WHERE AMD_CODE = :AMD_CODE*
*          AND MMA_AMD_CODE = AMD_CODE;*
*     IF cnt > 0 THEN*
Alerts.Stop_Alert('Error: IMDG Code '||:AMD_CODE||'Delete not allowed!!Exists in t_mmamd table', choice);
RAISE FORM_TRIGGER_FAILURE;                       
*          ELSE*
*          alert_title := 'Are you sure to remove this record ?';*
*          Alerts.Stop_Alert_YesNo (alert_title, p_button_choice);*
If p_button_choice = 1 Then
*     delete_record;*
End if;
END IF;
end;
Else -- record status is in INSERT or NEW mode
*          delete_record;*
*     End if;*
End;
It works okay and prevents me from deleting records in the other table . However I get the following errors when I try to delete a record which doesn't exist in t_mmamd table :
Could not resolve record(2 tries) keep trying?
Error : 40501 - oracle Error unable to reserve record for update or delete .