An Example of a Database

Before we move onto the example, we must identify the need to store data in tabular form.

One of the main reasons to store data regarding a specific object in a table is ease of understanding. So, instead of keeping relevant information regarding an object (like a student) in separate files, tables allow us to keep the important data regarding that object (like student ID, name, address, age, etc.) in one place.

A table is a collection of related data held in a table format within a database. It consists of columns and rows.

Column_1	Column_2	Column_3
Data_Item1	Data_Item2	Data_Item3
Data_Item4	Data_Item5	Data_Item6
…	…	…

Each row in a relational database represents one instance of the type of object described in that table. A row is also called a record. While the columns in a table are the set of facts that we keep track of regarding that type of object. A column is also called an attribute.

A university database example

Let’s consider a university database that is used to maintain information concerning students, courses, and departments in a university environment. The diagram below shows the database structure and a few sample data records.

Student Table

ID	First_Name	Last_Name	Class	Major
2001	Adam	Smith	Junior	CS
2342	Jonathan	Joestar	Sophomore	Economics
2343	Lucas	Klein	Senior	Physics

Course Table

Course_ID	Course_Name	Course_credits
CS200	Intro to programming	4
MATH100	Calculus-I	3
CS300	Advanced Programming	3

Department Table

Department_Code	Department_Name
1	Computer Science
2	Electrical Engineering
3	Physics
4	Biology

Instructor Table

Instructor_ID	Instructor_fname	Department_Code
12	Sam	1
22	Tom	2
04	David	3

Grade Table

ID	Course_ID	Grade
2001	CS200	A-
2220	EE100	C
2343	PHY220	B