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i + TYPES OF DATABASES
There are mainly two types of databases:
• Flat File Database: It is a type of database that contains records having a less
number of fields without any structured relationship between them. The most
popular example of a flat file database is Excel 2016. Excel 2016
• Relational Database: It is a type of database that stores
data in multiple tables and links those tables together
to retrieve the information. Commonly used relational
database systems are Microsoft Access, Microsoft SQL Server, ORACLE, etc.
Info Byte
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 (RDBMS).
i + TERMS RELATED TO A DATABASE
Data is stored in the table of a database, as shown in the diagram given below.
FIELDS
Primary
key
Reg No. Name Father’s Name Date of Birth Class
187/11 Krishna Kant Mr. K.S. Kant 15/08/2007 VIII
RECORDS 156/12 Rishi Sharma Mr. N.K. Sharma 22/10/2008 IX
194/11
16/04/2008
IX
Suraj Patel
Mr. G.S. Patel
123/12 Priyansh Sagar Mr. P.K. Sagar 18/06/2007 VIII
Table: Student's detail
The commonly used terms in a relational database are:
• Table: Table is also knowns as Relation. 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 columns are also known as a Fields. A set of
values for the fields is called a Record. A 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 the above table, 'Student's detail' the
'Reg No.' can be referred to as a primary key as it is always unique and never null.
• Query: A query is the most powerful object in a database. It helps you retrieve information
from a table based on some criteria or conditions. You can find and retrieve data from the
database by creating and running a query.
• Report: A report is a database object that is specially designed to display or print the data
in a formatted way. It is the final result of the manipulated data that comes from tables or
queries in a DBMS is known as a report.
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