Data Modeling

Assignment 3


1. Automata Inc. produces specialty vehicles by contract. The company operates several departments, each one of which builds a particular vehicle, such as a limousine, a truck, a van, or an RV.

When a new vehicle is built, the department places an order with the Purchasing Department to request specific components. Automata's Purchasing Department is interested in creating a database to keep track of orders and to accelerate the process of delivering materials.

The order received by the Purchasing Department can contain several different items. An inventory is maintained so that the most frequently requested items are delivered almost immediately. When an order comes in, it is checked to determine whether the requested item(s) is (are) in inventory. If an item is not in inventory, it must be ordered from a supplier. Each item may have several suppliers.

Given this functional description of the processes encountered at Automata's purchasing department, do the following using the crow’s foot model:

  1. Identify all the main entities
  2. Identify all the relations and connectivities among entities.
  3. Identify if the relationship is strong or weak.

Problem 1


2. Given the following brief summary of business rules for the ROBCOR catering service and using the Crow’s Foot E-R methodology, draw the fully labeled ERD. Make sure to include all appropriate entities, relationships, connectivities, and cardinalities.

  • Each dinner is based on a single entree, but each entree can be served at many dinners. A guest can attend many dinners and each dinner can be attended by many guests. Each dinner invitation may be mailed to many guests and each guest may receive many invitations

Problem 2


3. Given the following information, produce an ERD – based on the Crow’s Foot model -- that can be implemented. Make sure to include all appropriate entities, relationships, connectivities and cardinalities.

  • EverFail company is in the quick oil & lube business. Although customers bring in their cars for what is described as quick oil changes, EverFail also replaces windshield wipers, oil filters, and air filters, subject to customer approval. The invoice contains the charges for the oil used, all parts used, and a standard labor charge. When the invoice is presented, customers pay cash, use a credit card, or write a check. EverFail does not extend credit. EverFail's database is to be designed to keep track of all components in all transactions.
  • Given the high parts usage of the business operations, EverFail must maintain careful control of its parts (oil, wipers, oil filters, air filters) inventory. Therefore, if parts reach their minimum on hand quantity, the part in question must be reordered from an appropriate vendor. EverFail maintains a vendor list which contains both the vendors actually used as well as potential vendors.
  • Periodically, EverFail mails updates to customers, based on the date of the car's service. EverFail also tracks each customer's car mileage.

Problem 3