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Relational Databases
Clickipedia
The relational database was proposed by Edgar F. Codd. He gave a set of thirteen rules
(Codd’s rules) to define a Relational Database Management System.
ADVANTAGES OF A DATABASE SYSTEM
A database system has many advantages. Some of the important advantages are:
It minimizes the redundancy of data by integrating and sharing the data files.
It saves the storage space.
All the users are provided with some access rights or privileges and permissions.
The files can be easily updated whenever changes are being made.
TERMS RELATED TO A DATABASE
Data is stored in the table of a database, as shown in below diagram.
FIELDS
Father’s Name
Date of Birth
Name
Reg No. Aashi Kant Mr. P.S. Kant 15/08/2007 Class
VIII
187/11
RECORDS 156/12 Nazia Sharma Mr. R.K. Sharma 22/10/2008 IX
Rajesh Patel
194/11
16/04/2008
IX
Mr. V.S. Patel
123/12 Niraj Sagar Mr. A.K. Sagar 18/06/2007 VIII
The commonly used terms of the relational database are:
Table: It is a group of related data organised in columns and rows in a database. The columns
contain a number of headings such as Reg No., Name, Father's Name, Date of Birth, Class,
etc. These are known as Fields. A set of values for the fields is called a Record. Record is one
row of the table.
Primary Key: It is a unique field by which the records are uniquely identified in a table. A
table can have only one primary key. For example, in a student’s record the ‘Reg No.’ can be
called a primary key.
Query: A query is the most powerful feature of database. It helps you to retrieve information
from a table based on some criteria or condition. You can ask, find and retrieve data from
the database just by creating and running the query.
Introduction to LibreOffice Base 21

