Chapter 2, Problem 1RQ

Explanation of Solution

Entity:

Entity refers to the basic building block of data collected regarding a person, place, event, or thing.

• Entity can be defined as an object in the system that has to be modelled and about which information has to be stored.
• The property of entity refers to attribute and the association between entities refers to a relationship.
• Rectangles with either round or square corners are used to represent an entity.
• Entity is described by a singular noun spelled in capital letters.
• Some common examples of entities are Employee, Student, Lecturer, etc.

Example of entity:

The example of an entity is given below:

• Student – the student is the name of the person, who collects the details of the student information. Therefore, here the STUDENT acts as an entity.
• Lecturer - the lecturer is the person name, who collects the details of lecturer information. Therefore, here the Lecturer acts as an entity.
• Department - the department is the person name that collects the details of department information. So, here the Department acts as an entity.

The following example shows “Student” entity, “Lecturer” entity, and “Department” entity of the “college” database. The rectangle box is used to define an entity with name.