Database Questions

Due Saturday, April 15,2015

Consider a database used to record the marks that students get on different examinations of different course offerings.

(a)Construct an E-R diagram for the database that models exams as entities, and uses a ternary relationship. (5 points)

(b)Construct an alternative E-R diagram that uses only a binary relationship between students and course_offerings. Make sure that only one relationship exists between a particular student and course_offering pair, yet you can represent the marks that a student gets in different exams of a course offering. (5 points)

(c)Design an E-R diagram for keeping track of the exploits of your favorite sports team. You should store the matches played, the scores in each match, the players in each match, and individual player statistics for each match. Summary statistics should be modeled as derived attributes. (5 points)

(d)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. (5 points)

(e)A weak entity set can always be made into a strong entity set by adding to its attributes the primary key attributes of its identifying entity set. Outline what sort of redundancy will result if we do so. (5 points)