Updating Through Cursors

Go Up to Declaring a Cursor

In many applications, data retrieval and update may be interdependent. DECLARE CURSOR supports an optional FOR UPDATE clause that optionally lists columns in retrieved rows that can be modified. For example, the following statement declares such a cursor:

EXEC SQL
DECLARE H CURSOR FOR
SELECT CUST_NO
FROM CUSTOMER
WHERE ON_HOLD = '*'
FOR UPDATE OF ON_HOLD;

If a column list after FOR UPDATE is omitted, all columns retrieved for each row may be updated. For example, the following query enables updating for two columns:

EXEC SQL
DECLARE H CURSOR FOR
SELECT CUST_NAME CUST_NO
FROM CUSTOMER
WHERE ON_HOLD = '*';

For more information about updating columns through a cursor, see Updating Multiple Rows.