Lab Work 6-2 on ERD – Chapter 6
Consider the following processing requirements description of Dammam Electronic Hardware Management IS application: The Xtra electronic hardware company wishes to design and create a database for the sales IS application. A customer makes a purchase order for one or more hardware products such a computer, printer, iPod, etc. Once an order is completed an invoice is generated, then the customer is requested to make the payment. An invoice has invoice lines corresponding to ordered products. Each invoice line shows product code, description, and price. The ordered products will be shipped from a certain branch in Saudi Arabia, and a shipment slip will be generated from the branch and attached to the shipped package. Develop an entity relationship diagram model for this application. Do the following tasks when developing your ERD model: 1. Write the business rules
2. Determine entities, relationships, and relationship class (1-1, 1-M, and M-M). 3. Resolve M-M relationships.
4. For each entity, define a unique identifier and two more attributes. Business Rules:
Business Rule 1: a Customer makes more than one order (1: m). And an order made by one customer only. (1:1)
Business Rule 2:An invoice is generated for one order. (1:1) And an order has one invoice. (1:1)
Business Rule 3: An invoice has one or many invoice lines. (1:M). An invoice line has on invoice (1:1)
Business Rule 4: Order has one or more ordered items. An a ordered item belong to one order
Business Rule 5:Order items is associated with one product, and a product is associated with many orders .
Business Rule 6: an order comes from one branch . But order branch imports to many branches.
Entity Relationship Diagram (ERD) of the Xtra Electronic Hardware Management Information System -----------------------