Database Management System

1. Database Users and Administrators
A primary goal of a database system is to retrieve information from and store new information in the
database. People who work with a database can be categorized as database users or database
administrators.
Database Users and User Interfaces
There are four different types of database-system users, differentiated by the way they expect to interact
with the system. Different types of user interfaces have been designed for the different types of users.
1. Naive users – are unsophisticated users who interact with the system by invoking one of the permanent
application programs that have been written previously. The typical user interface for naive users is a forms
interface, where the user can fill in appropriate fields of the form. Naive users may also simply read reports
generated from the database.
E.g. people accessing database over the web, bank tellers, clerical staff.
2. Application programmers – are computer professionals who write application programs uses the
database. These application programs are written in programming languages like COBOL or PL
(Programming Language 1), Java and fourth generation language. These programs meet the user
requirement and made according to user requirements. Retrieving information, creating new information
and changing existing information is done by these application programs.
Application programmers can choose from many tools to develop user interfaces. Rapid application
development (RAD) tools are tools that enable an application programmer to construct forms and reports
without writing a program.
3. Sophisticated users – interact with the system without writing programs. They do not use any
application or programs to request the database. They directly interact with the database by means of query
language like SQL. These users will be scientists, engineers, analysts who thoroughly study SQL and
DBMS to apply the concepts in their requirement.
4. Specialized users – are sophisticated users who write specialized database applications that do not fit
into the traditional data-processing framework.
e.g., computer-aided design systems, knowledge-base and expert systems and environment-modeling
systems – uses complex data types.
Database Administrator
One of the main reasons for using DBMSs is to have central control of both the data and the programs that
access those data. A person who has such central control over the system is called a database
administrator (DBA). The functions of a DBA include:
 Schema definition. The DBA creates the original database schema by executing a set of data
definition statements in the DDL.
 Storage structure and access-method definition.

2.  Schema and physical-organization modification. The DBA carries out changes to the schema
and physical organization to reflect the changing needs of the organization, or to alter the physical
organization to improve performance.
 Granting of authorization for data access. By granting different types of authorization, the
database administrator can regulate which parts of the database various users can access. The
authorization information is kept in a special system structure that the database system consults
whenever someone attempts to access the data in the system.
 Migrate database servers - Sometimes, users using oracle would like to shift to SQL server or
Netezza. It is the responsibility of DBA to make sure that migration happens without any failure,
and there is no data loss.
 Routine maintenance. Examples of the database administrator’s routine maintenance activities
are:
 Periodically backing up the database, either onto tapes or onto remote servers, to prevent loss
of data in case of disasters such as flooding.
 Ensuring that enough free disk space is available for normal operations, and upgrading disk
space as required.
 Monitoring jobs running on the database and ensuring that performance is not degraded by
very expensive tasks submitted by some users.
Types of Database Administrator
There are different kinds of DBA depending on the responsibility that he owns.
 Administrative DBA - This DBA is mainly concerned with installing, and maintaining DBMS
servers. He is mainly responsible for all administrative tasks of a database.
 Development DBA - He is responsible for creating queries and procedure for the requirement.
Basically his task is similar to any database developer.
 Database Architect - Database architect is responsible for creating and maintaining the users,
roles, access rights, tables, views, constraints and indexes. He is mainly responsible for designing
the structure of the database depending on the requirement. These structures will be used by
developers and development DBA to code.
 Data Warehouse DBA -DBA should be able to maintain the data and procedures from various
sources in the datawarehouse.
 Application DBA -He acts like a bridge between the application program and the database. He
makes sure all the application program is optimized to interact with the database. He ensures all
the activities from installing, upgrading, and patching, maintaining, backup, recovery to executing
the records works without any issues.
 OLAP DBA - He is responsible for installing and maintaining the database in OLAP systems. He
maintains only OLAP databases.
A. S. M. Shafi
Lecturer
Department of Computer Science and Engineering
Khwaja Yunus Ali University
Enaytpur, Sirajgonj-6751, Bangladesh