You can override the WHERE clause to include non-key columns. For example, you might want to update records for employees named Mike Smith only. To do this, you edit the WHERE clause as follows:
UPDATE T_SALES SET DATE_SHIPPED = :TU.DATE_SHIPPED,
TOTAL_SALES = :TU.TOTAL_SALES WHERE :TU.EMP_NAME = EMP_NAME and
EMP_NAME = 'MIKE SMITH'