DATABASE SYSTEMS 3
Entities of a database and its attributes
In a database, an entity is any phenomenon such as a person, place, or an object which
data should be captured and stored in the form of properties and tables or workflows. In this
college, however, entities include tables, tutors, and offices. An attribute in a database defines
the information about the entity captured and stored. For instance, if an entity is the tutor name,
the attributes include; his names, ID, work location, and the courses that he handles. An entity
also may have zero or more attributes in the database. Each of the attributes of an entity applies
to one entity that is assigned. For instance, a student admission number of 96584 will belong to
one student entity alone and cannot be given to another student (Thalheim, 2013).
Attributes, on the other hand, have other refinements such as the domain and the key. The
domain of an entity only describes the possible values of attributes. In an entity, the attribute has
only one value which can be a number, time or text. Here are the examples of entities and
attributes that have been explained above.
Entities of a database include students, instructor, and the course.
Attributes of the entities are:
Students: Student ID number, first and last name, Index number, phone number, address, date,
gender and date of birth.
Course: Course name, department of the course, sections/units, tutor/instructor, and course ID.
Instructor: Name of the instructor, first and last name of the instructor, Instructor ID
Business rules that have an impact on the structure of a database
Business rules always have a major impact on the structure of a database. For instance,
the institution may need to store data in its encrypted form; hence it has to modify the base tables
to accommodate the number of the students and employees of the institution or look for the
