Sixth Chapter Lesson-2 Database Management System and Different types of Database.

In this Lesson you will learn-

  • 1. Concept of DBMS.
  • 2. The functions of DBMS.
  • 3. Advantages and disadvantages of DBMS.
  • 4. Different types of database.


DBMS: A database management system (DBMS) is one kind of system software for creating and managing  databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data. The DBMS essentially serves as an interface between the database and end users or application programs.

Some DBMS examples include MySQL, PostgreSQL, Microsoft Access, SQL Server, FileMaker, Oracle, dBASE, Clipper, and FoxPro.


Database Administrator (DBA): Database administrator is an individual who is responsible for the maintenance and operation of database to keep the data secure.

A database administrator’s responsibilities can include the following tasks: 

  • 1. Installing and upgrading the database server and application tools.
  • 2. Allocating system storage and planning storage requirements for the database system.
  • 3. Modifying the database structure as necessary.
  • 4. Enrolling users and maintaining system security.
  • 5. Controlling and monitoring user access to the database.
  • 6. Monitoring and optimizing the performance of the database.
  • 7. Planning for backup and recovery of database information.
  • 8. Backing up and restoring databases.
  • 9. Generating various reports by querying from database as per need.
  • 10. Managing and monitoring data replication.


Functions of DBMS:

  • 1. Data dictionary management
  • 2. Data storage management
  • 3. Data transformation and presentation
  • 4. Security management
  • 5. Multiuser access control
  • 6. Backup and recovery management
  • 7. Data integrity management
  • 8. Database access interfaces
  • 9. Database communication interfaces
  • 10. Transaction management.


Advantages and disadvantages of DBMS:


  • Better data sharing: The DBMS helps create an environment in which end users have better access to more and better-managed data.
  • Improved data security: A DBMS provides a framework for better enforcement of data privacy and security policies.
  • Improved data integration: It becomes much easier to see how actions in one segment of the company affect other segments.
  • Minimized data inconsistency: Data inconsistency exists when different versions of the same data appear in different places. The probability of data inconsistency is greatly reduced in a properly designed database.
  • Improved data access: The DBMS makes it possible to produce quick answer to ad hoc queries.
  • Improved decision making: The availability of data, combined with the tools that transform data into usable information, empowers end users to make quick, informed decisions that can make the difference between success and failure in the global economy.


  • Increased costs: Database systems require sophisticated hardware and software and highly skilled personnel. The cost of maintaining the hardware, software, and personnel required to operate and manage a database system can be substantial.
  • Management Complexity: Database systems interface with many different technologies and have a significant impact on a company’s resources and culture.
  • Maintaining currency: To maximize the efficiency of the database system, you must keep your system current. You must perform frequent updates and apply the latest patches and security measures to all components.
  • Frequent upgrade/replacement cycles: DBMS vendors frequently upgrade their products by adding new functionality. Such new features often come bundled in new upgrade versions of the software. Some of these versions require hardware upgrades. Not only do the upgrades themselves cost money, but it also costs money to train database users and administrators to properly use and manage the new features.


Types of Database: Based on database architecture, database are three types.

  • 1. Server-client database
  • 2. Distributed database
  • 3. Web enable database


Server-client database: In the Server-client architecture, the database application and the database are separated into two parts: a front-end or client portion, and a back-end or server portion. The client executes the database application that accesses database information and interacts with a user through the keyboard, screen, and pointing device such as a mouse. The server executes the database software and handles the functions required for concurrent, shared data access to database.


Distributed database: A distributed database is a collection of multiple interconnected databases, which are spread physically across various locations that communicate via a computer network.

Databases in the collection are logically interrelated with each other. Often they represent a single logical database. Data is physically stored across multiple sites. Data in each site can be managed by a DBMS independent of the other sites. The processors in the sites are connected via a network. They do not have any multiprocessor configuration. A distributed database is not a loosely connected file system. A distributed database incorporates transaction processing, but it is not synonymous with a transaction processing system.


Web enable database: A web-enabled database system provides interactive access to business information, making queries, placing orders, reporting, tracking and updating records via the internet and the browser.  In other words, standard database features and functions but accessed remotely. That’s what it is called a web-enabled database application.


Lesson Evaluation-

  • a.What is DBMS?
  • a.What is database administrator?
  • b.Explain the role of database administrator in database.
  • b.Is it needed to validate data in DBMS? Explain it.


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