Listing 2. Shopping Cart Data Structures

# # create a sequence which we'll use to generate # customer id's. I'm separating each id by # an arbitrary number so that there is some space # between each new customer to reduce the odds # that you could guess someone else's cart number # create sequence seq_customer_id increment 26 start 1; create table customers ( customer_id int not null default 0 primary key, name text, address text, credit_card text, total_order MONEY DEFAULT '$0.00' ); create table cart_items ( cart_item serial, customer_id int, part_number int, quantity int ); create index idx_cart_customer on cart_items(customer_id); create table item_inventory ( part_number serial, name text, price float, inventory int );