Assignment 4: Due EOD Monday, February 18; no later assignments will be accepted.

All answers & diagrams must be included in a single Word or PDF file.

1. Explain the distinctions among the terms primary key, candidate key, and superkey.

2. Define each of the following: Weak Entity, Multi-valued Attribute, Weak Relationship

To answer exercises 3 & 4, you will be providing most of the entities, attributes, and relationships for a given database in the form of an E-R diagram. Since many of the database requirements are not given; it is up to you to design the databases (one per exercise) and to include the information you are given into the overall E-R diagram design --other than the inclusion of the information in each exercise, there is not one right database design.

Note: These diagrams should not be hand-written; you must use an online diagramming tool or a product such as Visio

3. Construct an E-R diagram for a car insurance company whose customers own one or more cars each. Each car has associated with it zero to any number of recorded accidents.

4. Construct an E-R diagram for a hospital with a set of patients and a set of medical doctors. Associate with each patient, a log (hint: relationship) of the various tests and examinations conducted.