Update specific columns

The following example has updated specific columns of the preceding example of an update cursor: 
EXEC SQL
   DECLARE names CURSOR FOR
      SELECT fname, lname, company, phone
         INTO  :FNAME,:LNAME,:COMPANY,:PHONE FROM customer
   FOR UPDATE OF fname, lname
END-EXEC.
Only the fname and lname columns can be updated through this cursor. A statement such as the following one is rejected as an error: 
EXEC SQL
   UPDATE customer
      SET company = 'Siemens'
      WHERE CURRENT OF names
END-EXEC.

If the program attempts such an update, an error code is returned and no update occurs. An attempt to delete with WHERE CURRENT OF is also rejected, because deletion affects all columns.