example ?

BEGIN TRAN
IF !TABLEUPDATE(2,.T.,"mrn")
=AERROR(ERRORARRAY)
DO CASE
CASE ERRORARRAY(1)=1884
m.msg="M.R.N already exists "
=MESSAGEBOX(m.msg,16,m.productname +"Message")
ROLLBACK
* thisform.command1.setfocus
RETU 0
CASE ERRORARRAY(1)=1539
m.msg="Cannot be modified"
=MESSAGEBOX(m.msg,16,m.productname +"Message")
ROLLBACK
* thisform.command1.setfocus
RETU 0
ENDCASE

ENDIF

*** by ra - remove seperate begin tran endtran
sele godown
=TABLEUPDATE(.T.)
END TRAN