Imagine you own an online pet store called House-O-Pets.com.
You use an Oracle database schema to keep track of inventory, customers, and customer purchases.
Because you are selling real live pets, you have a real pet store as well, with several employees to take care of the animals. You get orders from customers all around the country. You have rabbits, puppies, kittens, fish, and birds in your store.
Your inventory includes pet supplies for all these animals. Customers can purchase any item individually. In addition, two packages that include a set of related items sell at a discount.
For example, the Puppy Package comes with a puppy, dog food, a chew toy, and a dog collar. To help your employees care for the animals, your database contains a pet care log, where any employee can record information about the animals, such as how often to feed the birds.
The pet store schema shown above contains a set of related tables.
In addition to the five tables, there is a view called MONTHLY_SALES that lists total sales for each month/year combination.
There is also a sequence called PETSTORE_SEQ that generates unique primary key values for the PRODUCT, CUSTOMER, and CUSTOMER_SALE tables. In the next module, PL/SQL variable declaration will be discussed.