How To Use "IN" Parameter Properly

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How To Use "IN" Parameter Properly? - Oracle DBA FAQ - Creating Your Own PL/SQL Procedures and Functions

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A

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) := 'FYICenter.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 FYICenter.com

2007-04-25, 5456👍, 0💬

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