This figure repeats the graphic representation of the HR schema (described in the preceding graphic). It also describes the OE schema and shows the dependencies between the two schemas.
Within the OE schema:
The order_items table has the columns order_id (primary key), line_item_id (primary key), product_id, unit_price, and quantity. Each order item may be associated with one or more products in the product_information table and must be associated with one order in the orders table.
The product_information table has the columns product_id (primary key), category, weight_class, warranty_period, supplier_id, product_status, list_price, min_price, and catalog_url. Each product must be associated with one product description, and may be associated with one or more order items in the order_items table and one or more products in the inventories table.
The orders table has the columns order_id (primary key), order_date, order_mode, customer_id, ship_mode, order_status, sales_rep_id, and order_total. Each order must be associated with one customer from the customers table and with one or more order items from the order_items table.
The product_descriptions table has the columns product_id (primary key), language_id (primary key), product_name, and product_description. Each product may have one or more associations with the product_information table.
The inventories table has the columns product_id (primary key), warehouse_id (primary key), and quantity_on_hand. Each product in the inventories must have at least one association with a product in the product_information table and a warehouse in the warehouses table.
The customers table has the columns customer_id (primary key), cust_first_name, cust_last_name, cust_address_typ, phone_numbers, credit_limit, cust_email, account_mgr_id, nls_language, and nls_territory. The cust_address_typ column is an object column with the attributes street_address, postal_code, city, state_province, and country_id. Each customer may have one or more associations with the orders table.
The warehouses table has the columns warehouse_id (primary key), warehouse_name, and location_id. Each warehouse may have one or more associations with the products in the inventories table.
Between the HR and OE schemas:
Each employee in the hr or employees table may have one or more associations with order in the oe.orders table. Each order in the oe.orders table must have one association with the hr.employees table.
Each employee in the hr.employees table may have one or more associations with the oe.customers table. The oe.customers table may have at least one association with the hr.employees table and with the hr.regions table.
Each customer in the oe.customers table may have one association with the hr.regions table. Each region in the hr.regions table may be associated with multiple customers in the oe.customers table.
Each warehouse in the OE schema must be related to one location in the HR schema, and each location in the HR schema may be associated with one warehouse in the OE schema.