How To Use "IN OUT" Parameter Properly
Q
How To Use "IN OUT" Parameter Properly? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions
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A
Here are the rules about IN OUT parameters:
- A formal IN OUT parameter acts like an initialized variable.
- An actual IN OUT parameter must be a variable.
- An actual IN OUT parameter passes a copy of its value to the formal parameter when entering the procedure or function.
- An actual IN OUT parameter will receive a copy of the value from the formal parameter at the end of the procedure or function.
Here is good example of a procedure with IN OUT parameters:
SQL> CREATE OR REPLACE PROCEDURE SWAP_TEST AS
2 A NUMBER := 3;
3 B NUMBER := 8;
4 PROCEDURE MY_SWAP(X IN OUT NUMBER,Y IN OUT NUMBER) AS
5 T NUMBER;
6 BEGIN
7 T := X;
8 X := Y;
9 Y := T;
10 END MY_SWAP;
11 BEGIN
12 MY_SWAP(A,B);
13 DBMS_OUTPUT.PUT_LINE('A = ' || TO_CHAR(A));
14 DBMS_OUTPUT.PUT_LINE('B = ' || TO_CHAR(B));
15 END;
16 /
SQL> EXECUTE SWAP_TEST;
A = 8
B = 3
2007-04-21, 5747👍, 0💬
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