PL/SQL User's Guide and Reference

Overloading

Recall from Chapter 7 that PL/SQL allows two or more packaged subprograms to have the same name. This option is useful when you want a subprogram to accept parameters that have different datatypes. For example, the following package defines two procedures named journalize:

CREATE PACKAGE journal_entries AS
   PROCEDURE journalize (amount NUMBER, trans_date VARCHAR2);
   PROCEDURE journalize (amount NUMBER, trans_date NUMBER );
END journal_entries;

CREATE PACKAGE BODY journal_entries AS
   PROCEDURE journalize (amount NUMBER, trans_date VARCHAR2) IS
   BEGIN
      INSERT INTO journal
         VALUES (amount, TO_DATE(trans_date, 'DD-MON-YYYY'));
   END journalize;

   PROCEDURE journalize (amount NUMBER, trans_date NUMBER) IS
   BEGIN
      INSERT INTO journal
         VALUES (amount, TO_DATE(trans_date, 'J'));
   END journalize;
END journal_entries;

The first procedure accepts trans_date as a character string, while the second procedure accepts it as a number (the Julian day). Yet, each procedure handles the data appropriately.