Package - customer_package
customer_package is a package that contains types, procedures and functions related to customer management.
- create_customer - Creates customers with verification of duplicate values
- generate_promotion:- Generates a list of customers who are eligible for the
company's promotion based on the birth date
- search_customer_records:- Returns a list of the customers in the form of the reference cursor

Demonstrated features
- Anchor Data types:
- Advanced type support:-
- TYPE ... IS RECORD ...
- TYPE ... IS REF CURSOR
- TYPE ... IS TABLE OF ... INDEX BY ...
- Dynamic statement execution:-
- Built-in Functions:-
- Exceptions:-
- EXCEPTION ... WHEN ... THEN ...
- RAISE