Assignment 5 Decomposition of many:many relationships for MIS208 Data Analysis

MIS208 Data Analysis

Assignment 5   Decomposition of many:many relationships

Set: 28 March 2014                                                    Due:  4 April 2014

p.111, Q1, Q2

Questions

1. The following table shows which suppliers supply which parts.

supplierNo	partNo
S1	P15
S1	P29
S1	P32
S2	P12
S2	P15
S3	P12
S3	P32

(a) Draw an entity-relationship type diagram showing a single relationship between

entity types Supplier and Part.

(b) Decompose your diagram into an equivalent diagram containing only 1:many

relationship types.

(c) Draw an entity-relationship occurrence diagram showing the above data as two

1:many relationships.

2. A college runs many evening classes (e.g. metalwork, pottery, art, local history).

Each class may be taught by several teachers, and a teacher may teach several classes.

A particular class always uses the same room (e.g. pottery always uses room R12).

Because classes may meet at different times or on different evenings it is possible for

different classes to share a room (e.g. pottery and art both use room R12).

(a) Draw an entity-relationship type diagram showing the entity types Teacher,

Class, Room and the relationship types TeacherClass and RoomClass.

(b) Re-draw your type diagram, decomposing any many:many relationship into

1:many relationships.