Database Design and Data Modeling: Assignment 2

Mohammed Azrak

Kaplan University

Database Design and Data Modeling: Assignment 2

Question #1 Definitions:

Define each of the following terms (1 pt. each). In addition, provide an example of each term (2 pts. each). a. Business Rule b. Entity c. Entity Set (Entity Type) d. Entity Instance e. Attribute f. Relationship g. Connectivity h. Cardinality Constraint i. Participation Constraint. j. Associative Entity

Answer #1:

a. Business Rule – a description of a policy, procedure or principle within an organization. For example, truck drivers can only drive for 60 or 70 hours in the last seven or eight days.

b. Entity – A person, place or thing for which data can be stored. For example, an airport is an entity that has many airlines within it.

c. Entity Set (Entity Type) – A grouping of related entities in a relational model. For example, all airlines having a gate at an airport.

d. Entity Instance – is an individual occurrence of an entity type. For example, if a family had three children, Peter, Michael, and Sophie, each child (Peter, Michael, and Sophie) would be an instance of the ‘child’ entity.

e. Attribute – is a characteristic of an entity or an object. For example, Southwest Airlines is an attribute of entity ‘Airline’.

f. Relationship – An association between entities. For example, an airport has a relationship with airline where there are many airlines to one airport.

g. Connectivity – is the classification of the relationship between entities. These classifications include 1:1, 1:M, and M:N. For example the connectivity of the relationship between airport to airline would be 1:M. h. Cardinality Constraint – is when a