Package - product_package
product_package is a package that contains procedures related to product management.
- create_product - Creates customers with verification of duplicate values
- verify_product_availability - Generates a list of customers who are eligible for the
company's promotion based on the birth date
- write_catalog - Returns a list of the customers in the form of the reference cursor

Demonstrated features
- Definitions:-
- CREATE OR REPLACE PACKAGE ... IS
- CREATE OR REPLACE PACKAGE BODY... IS
- CREATE OR REPLACE PROCEDURE ... IS
- CREATE OR REPLACE FUNCTION ... IS
- Cursor Support:-
- CURSOR ... IS SELECT ...
- OPEN, FETCH, CLOSE
- %FOUND, %NOTFOUND, %ISOPEN
- PL/SQL syntax:-
- := - assignment
- /* ... */ - block comments
- Built-in packages:-
- DBMS_OUPUT
- UTL_FILE
- UTL_DIR
- New SQL syntax:-
- ... START WITH ... CONNECT BY PRIOR ...
- LEVEL
- (+) - outer join
- New sequences keywords:-