Oracle Database Interview Question:

How To Use "IN" Parameter Properly?

Submitted by: Administrator

Here are the rules about IN parameters:

► A formal IN parameter acts like constant. It can not be assigned with new values.
► An actual IN parameter can take a value or a variable.
► An actual IN parameter is passed by reference to the specified value or the value of the specified variable.
► An actual IN parameter will not receive any value from the formal parameter.

Here is good example of a procedure with an IN parameter:

SQL> CREATE OR REPLACE PROCEDURE WELCOME AS
2 SITE CHAR(80) := 'globalguideline.com';
3 PROCEDURE WELCOME_PRINT(S IN CHAR) AS
4 BEGIN
5 DBMS_OUTPUT.PUT_LINE('Welcome to ' || S);
6 -- S := 'Google.com'; -- Not allowed
7 END;
8 BEGIN
9 WELCOME_PRINT('MySpace.com');
10 WELCOME_PRINT(SITE);
11 END;
12 /

SQL> EXECUTE WELCOME;
Welcome to MySpace.com
Welcome to globalguideline.com

Submitted by: Administrator