Tamilnadu Samacheer Kalvi 12th Computer Science Notes Chapter 11 Database Concepts Notes

Data and Information.

  • Data are raw facts stored in a computer
  • Information is formatted data


  • Database is a repository collection of related data organized in a way that data can be easily accessed, managed and updated.
  • Database can be a software or hardware based, with one sole purpose of storing data.


DBMS is a software that allows us to create, define and manipulate database, allowing users to store, process and analyze data easily.
Example: D base, Foxbase, Foxpro

Data consistency:
Data Consistency means that data values are the same at all instances of a database

Components of DBMS:
The Database Management System can be divided into five major components namely

  1. Hardware
  2. Software
  3. Data
  4. Procedures / Methods
  5. Database Access Languages

1. Hardware:
The computer, hard disk, I/O channels for data, and any other physical component involved in storage of data

2. Software:

  • This main component is a program that controls everything.
  • The DBMS software is capable of understanding the Database Access Languages and interprets into database commands for execution.

3. Data:
It is that resource for which DBMS is designed. DBMS creation is to store and utilize data.

4. Procedures/Methods:
They are general instructions to use a database management system such as installation of DBMS, manage databases to take backups, report generation, etc

5. DataBase Access Languages:
They are the languages used to write commands to access, insert, update and delete data stored in any database. Examples of popular DBMS : Dbase, FoxPro

Normalization is a technique of organizing the data in the database.

Types of DBMS Users:

1. Database Administrators:

  • Database Administrator or DBA is the one who manages the complete database management system.
  • DBA takes care of the security of the DBMS, managing the license keys, managing user accounts and access etc.

2. Application Programmers or Software Developers:
This user group is involved in developing and designing the parts of DBMS.

3. End User:

  • All modern applications, web or mobile, store user data.
  • Applications are programmed in such a way that they collect user data and store the data on DBMS systems running on their server.
  • End users are the one who store, retrieve, update and delete data.

4. Database Designers:
Database Designers are responsible for identifying the data to be stored in the database for choosing appropriate structures to represent and store the data.

Different types of a Data Models:

  1. Hierarchical Model
  2. Relational Model
  3. Network Database Model
  4. Entity Relationship Model
  5. Object Model.

Samacheer Kalvi 12th Computer Science Notes