[Block based on From Query] On-Lock Trigger

Question

Hi,
I have a block based on an Emp_Dept view.
I manage updating and inserting with the On-Update and On-Insert triggers.
I wonder if I have to code this in the On-Lock trigger:
message( 'Oracle locks' );
lock table emp in share row exclusive mode;
If I want Oracle to prevent another user from updating the same row I'm updating.
Thanks for your help.
JBM

Answer 1

This is the code we use to lock specific records in ON-LOCK:
CURSOR crLock IS
  RESOURCE_BUSY EXCEPTION;
  PRAGMA EXCEPTION_INIT(RESOURCE_BUSY, -54);
  SELECT ID
    FROM THE_BASE_TABLE_OF_THE_VIEW
   WHERE ID=:BLOCK.ID FOR UPDATE OF ID NOWAIT;
  nDummy NUMBER;
BEGIN
  OPEN crLock;
  FETCH crLock INTO nDummy;
  CLOSE crLock;
EXCEPTION
  WHEN RESOURCE_BUSY THEN
    message('record cannot be locked');
    RAISE FORM_TRIGGER_FIALURE;
END;