Purpose of DBMS and users of DBMS

1. Purpose & Users of
DBMS

2. Index
1. Introduction of DBMS
2. Purpose of DBMS
1) Data Redundancy
2) Inconsistency
3) Difficulties in accessing data
4) Data isolation
5) Integrity Problem
6) Atomicity Problem
7) Concurrent Access Anomalies
8) Security Problem
3. Users of DBMS
1) Naive Users
2) Application Programmers
3) Sophisticated Users
4) Specialized Users

3. Introduction of
DBMS
Database:
Collection of interrelated data and Some
programs to access those data.
Database Management System:
Software Designed to assist in maintaining
and utilizing large collection of Data.

4. Purpose of
DBMS

5. Data
Redundancy
 Data can appear multiple times in a database for variety of
reasons. These is called Data redundancy.
 It results into wastage of storage space
 Decreases efficiency of database
 May cause data corruption
 DBMS prevents this issue from taking place.

6. Data
Inconsistency
 Redundancy leads to higher storage and access cost.
 Inconsistency is really corollary of Redundancy.
 Various copies of same data may no longer agree. It’s called
Inconsistency.
 Leads to incorrect data supply.

7. Difficulties in
accessing
data
 In typical file-processing system , permanent records are
stored in various files.
 Which makes accessing data very difficult.
 Where as in DBMS data can be be accessed in seconds.
 The point here is that conventional file-processing
environments do not
allow needed data to be retrieved in a convenient and efficient
manner.
 Moreresponsive data-retrieval systems are required for general
use.

8. Data
isolation
 In conventional file-processing system data is stored in different
formats.
 It was difficult to write new application programs in file-
processing system .
 Only at that time the concept of DBMS emerges for the rescue
of a large number of organizations.

9. Integrity
Problem
 The data values stored in the database must satisfy certain
types of consistency constraints.
 In conventional file-processing system constraints cannot be
applied .
 Suppose also that the university requires that the account
balance of a department may never fall below zero.
 It can be done in DBMS enforcing these constraints
in the system by adding appropriate code in the various
application programs.

10. Atomicity
Problem
 A computer system, like any other device, is subject
to failure.
 Clearly, it is essential to database consistency that either both
the credit and debit occur, or that neither occur.
 That is, the funds transfer must be atomic—it must happen in
its entirety or not at all.
 It is difficult to ensure atomicity in a conventional file-
processing system.

11. Concurrent
Access
Anomalies
 There may be a possibility that two users are maintaining same
files data for different applications.
 Anomalies occur when changes made by one user gets lost
because of changes made by other user.
 So DBMS helps to prevent Concurrent Access Anomalies in data.

12. Security
Problem
 Data security means prevention of data accession by
unauthorized users.
 conventional file-processing system don’t have any security
measures.
 Wheres DBMS has features of data security to protect data
from unauthorized users.

13. users
 Naïve : Any user who does not have any knowledge about
database can be in this category.
 Application Programmers : application programmers are the one
who writes application programs that uses the database.
 Sophisticated Users - They are database developers, who write
SQL queries to select/insert/delete/update data.
 Specialized Users : The sophisticated users who write
special database application programs are called specialized
users. The write complex programs for the specific complex
requirements.