Returning to the dellstore2 example database used in Chapter 10, Query Optimization, consider the structure of the orders table:
dellstore2=# \d orders; Table "public.orders" Column | Type | Modifiers -------------+---------------+-------------------------------- orderid | integer | not null default nextval('orders_orderid_seq'::regclass) orderdate | date | not null customerid | integer | netamount | numeric(12,2) | not null tax | numeric(12,2) | not null totalamount | numeric(12,2) | not null Indexes: "orders_pkey" PRIMARY KEY, btree (orderid) "ix_order_custid" btree (customerid) Foreign-key constraints: "fk_customerid" FOREIGN KEY (customerid) REFERENCES customers(customerid) ON DELETE SET NULL Referenced by: TABLE ...
