Database – What is Database Management System & Their Components

Database Management System NotesDatabase 


  • Facts in raw form are called data.
  • Data have no meaning.
  • (i.e.) 65, Farooq , age


  • Meaningful / Organized form of data is called information.
  • (i.e.) The age of Nasir is 65.


Drawbacks of File System are

Data Redundancy (Same data was duplicated in many different files)

Data Inconsistency (When same data are held in different files,the data has to be updated in all files. If any file may fail to update it will produce wrong output)

Program-data Dependence (If we want to change/modify structure of file, that means every program which uses that file has to be changed)

Lack of Flexibility (When non-routine information is needed, it takes many week to collect data from different files and write new programs to produce required result)

Data was not Shareable (Data of one department can’t shareable by other departments )


  • A collection of information organized in such a way that a computer program can quickly select required data.
  • OR

A Database is a collection of related data.

  • Database is just like an Electronic Filing System
  • (e.g.)

Computerized Library Systems

Automated Teller Machines (ATM) Flight Reservation Systems (etc)

Advantages of Database System:

Following are the main advantages of Database System

  • ü      More information from same data
  • ü      Shared data
  • ü      Balancing conflicts among users
  • ü      Controlled Redundancy
  • ü      Consistency
  • ü      Security
  • ü      Increased productivity
  • ü      Data independence

Fields, Records, Files and Database:

Fields (Columns are called Fields) Records (Rows are called Records)

Files (A file is a collection of records)

Database (A Database may have many files)


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