Referencing Oracle Database PL/SQL Functions in a WHERE Clause
A user-defined PL/SQL function in the Oracle database can be invoked indirectly in a
WHERE
clause within a CREATE CACHE GROUP
, LOAD CACHE
GROUP
, or REFRESH CACHE GROUP
(for dynamic cache groups only)
statement.
After creating the function, create a public synonym for the function. Then
grant the EXECUTE
privilege on the function to PUBLIC
.
For example, in the Oracle database:
CREATE OR REPLACE FUNCTION get_customer_name (c_num sales.customer.cust_num%TYPE) RETURN VARCHAR2 IS c_name sales.customer.name%TYPE; BEGIN SELECT name INTO c_name FROM sales.customer WHERE cust_num = c_num; RETURN c_name; END get_customer_name; CREATE PUBLIC SYNONYM retname FOR get_customer_name; GRANT EXECUTE ON get_customer_name TO PUBLIC;
Then in the TimesTen database, for example, you can create a cache group with a WHERE
clause that references the Oracle Database public synonym that was created for the function:
CREATE READONLY CACHE GROUP top_customer FROM sales.customer (cust_num NUMBER(6) NOT NULL, region VARCHAR2(10), name VARCHAR2(50), address VARCHAR2(100), PRIMARY KEY(cust_num)) WHERE sales.customer.name = retname(100);
For cache group types that allow a WHERE
clause on a LOAD CACHE GROUP
or REFRESH CACHE GROUP
statement, you can invoke the function indirectly by referencing the public synonym that was created for the function. For example, you can use the following LOAD CACHE GROUP
statement to load the AWT cache group new_customers
:
LOAD CACHE GROUP new_customers WHERE name = retname(101) COMMIT EVERY 0 ROWS;