Database Management system
A database management system is a collection of interrelated data and a
set of programs to access those data.
It manages new large amount of data and supports efficient access to new large amount of data.
Known facts that can be stored or recorded is called data.
It can be of two types:-
Persistent Data - It continues to exist, when the system is not avtive.
Transient Data - It created while an application is running and not
needed, when the application has terminated. It must be stored in
Database is collection of related data with :-
* A logically coherent structure (can be characterised as a whole).
* Some inherent meaning (represents some partial view of a portion of the real world).
* Some specific purpose and for an intended group of users and applications.
* A largely varying size(from a personal phone book directory to the phone book directory of a city or state).
* A scope or content of varing breadth(from a personal list of addresses to a multimedia encyclopedia).
* A physical organisation of varying complexity (from a manual personal list, managed with simple files, to huge multiuser databases with geographically distributrd data and access).
The information contained in a database is
represented on two levels :-
(i) Data (which is large and is being frequently modified)
(ii) Structure of data (Which is small and stable in time)
Basic Concept of DBMS
It is a collection of general purpose, application independent programs
providing services to:-
* Define the structure of a database, i.e. data types and constraints that the data will have to satisfy.
* Manage the storage of data, safely for long periods of time, on some storage medium controlled by the DBMS.
* Manipulate a database, with efficient user inferfaces to query the database to retrieve specific data, update the database to reffect changer in the world, generate reports from the data.
* Manage database usage for users with their access rights, perfomance optimisation, sharing of data among several users,security from accidents or unauthorised use.
* Monitor and analyse database usage.
Database Management System (DBMS) provides efficient, reliable, convenient and safe multiuser storage of and access to massive amounts of persistent.