Database Management System (DBMS)

What is Database Management System?


A   database   management   system   (DBMS)   consists   of   a collection of interrelated data and a set of program to access those data. The collection of data, usually referred to as the database, contains information about one particular    enterprise.    The   primary   goal   of   DBMS   is   to provide   an environment that is both convenient and efficient to use in retrieving and storing database information.

Example of database management systems are MS Access, DB2, ORACLE, SQL Server, MySQL, Ingress, Paradox, SYBASE, INFORMIX, etc.

Database systems are designed to manage large bodies of information.  The management of data involves both the definition of structures for the storage of information and provision of   mechanism   for   the   manipulation   of information.  In addition, the database system must provide for the safety of information stored despite the system crashes or attempts at unauthorized access.  If the data ate to be shared among several users, the system must avoid possible anomalous results. The importance of information  in most of the organization  which determine  the value of the database  has led to the development   of  large   bodies   of  concepts   and  techniques   for  efficient management  of data.

The database management system is the major software component of a database system. A database management system, therefore, is a combination of hardware and software that can be used to set up and monitor a database, and can manage the updating and retrieval of the database that has been stored in it. Most database management systems have the following facilities/ or capabilities:

  • Creating of a file, addition to data, deletion of data, modification of data; creation, addition and deletion of entire files.
  • Retrieving data collectively of selectively.
  • The data stored can be sorted or indexed at the user’s discretion and direction.
  • Various reports can be produced from the system. These may be either standardized reports or that may be specifically generated according to specific user definition.
  • Mathematical functions can be performed and the data stored in the database can be manipulated with these functions to perform the desired calculations.

Further we will discuss detail of DBMS’s facilities in Advantages of DBMS’.

Objective of DBMS

  1. Provide for mass storage device of relevant data.
  2. Making access to the data easy for the user.
  3. Providing prompt response to user request for data.
  4. Making the latest modification to the database available immediately.
  5. Eliminate redundant (duplicate) data.
  6. Allow multiple users to be active at one time.
  7. Allow the growth of database system.
  8. Protect the data from physical harm and unauthorized access.

Consider parts of a saving-bank enterprise that keeps information about all customer   and saving account. One  way  to  keep  the  information  on  a computer   is  to  store   it  in  permanent   system  files.   To allow users to manipulate   the   information,   the   system   has a number of   application programs that manipulate the files, including;

  • A program to debit or credit an account.
  • A program to add a new account.
  • A program to generate monthly statements.
  • A program to find balance of an account.

New application programs are added to the system as the need arises.

Application development without DBMS:

(File Processing System)

The typical file processing system is supported by a conventional operating system. The system stores permanent records in different files and it needs different application programs to extract records from file and to add records into files. Before the emergence of DBMS, organization stored information in file system. Keeping organizational data in file processing system has various disadvantages and some of them are:

  1. Data Redundancy and Inconsistency: Redundancy means repetition of same data item in many places within a data file. In a file processing system, there exists many chances of data redundancy. Due to redundancy, there occurs wastage of storage space and difficulty in modifying data. The same data item may be in different form or format in various places within a data file and it is known as data inconsistency.
  2. Difficulty in Accessing Data: In file processing system, different data files are used to store different information and we need different application programs to access those data files. So, it is difficult in accessing data in a file processing system.
  3. Integrity Problems: Data integrity means data contained in a database is both accurate and consistent. To maintain the integrity of data file processing system does not provide any facility.
  4. Atomicity Problems (“Do All or Do Nothing”): In file processing system, the transaction operating on data files are not atomic. So, if a transaction fails after performing partial operations, the database may be in an inconsistent step and this problem is known as atomicity problem.
  5. Concurrent Access Anomalies: Due to the concurrent or parallel access of same data file by multiple users at the same time there may exist some problems and it is known as concurrent access anomaly.
  6. Security Problems: File processing system does not provide any facility for the security and privacy of data files.
  7. Data Dependency: In file processing system, data files and programs are totally dependent on each other. If we want to make any changes on data files, then we have to make according changes in program as well and vice-verse.
  8. Limited Data Sharing: Single user can only access a data file in file processing system. So, data sharing is limited.
  9. Poor Programmers Productivity: Efficiency of programmers is reduced in file processing system due to the complexity of combining data files and program files.
  10. Excessive Program Maintenance: If we have to make some changes in a program then that change has to be done in many places within a program and data file. So, it requires excessive program maintenance.
  11. No facility for Backup and Recovery: File processing system does not provide facility for creating automatic backup and recovery of data in case of any type of failure.