Database Management System(DBMS)

Data and Information

Data is an unprocessed raw fact which does not give complete meaning about any object,person, entity etc. But when various inter-related data arranged in a row, it gives a complete meaning which is referred to as information. For Example:

ID	Name	Address	Program
1101	Ram Shrestha	Biratnagar	BScIT

is information of a specific person.

Database

Database is a repository(storage) for the organized collection of related information of data items. It Consist of meaningful arrangement of data, relationship, constraints, schema etc. In modern days we define database as a computerized record-keeping system used to store information and allows users to retrieve and update these information on their request. Some example of databases are telephone directory, data of SLC result, student and employee records etc.

Database Management System(DBMS)

Database is the software the software package to manage the database. It provides the environment for user to store, manipulate, update retrieve or delete the data of database whenever required. DBMS is the communicator program between users and database. It is master database software that control all the database and helps to preserve the consistency, integrity, security and non redundancy of data. Some example of DBMS are MS access, oracle, Cbase, Dbase etc.

fig: Simple view of Database System

Advantages of DBMS

1. Control Data Redundancy

DBMS do not allow to store same data files in the system which is already in system. I controls duplication of data because of this, it save space for new entry, help to find correct and updated file.

2.Data Access

Users can access data easily within the database with the help of DBMS.

3. Multiple User Interface

Multiple user can view the data in a same time without any problem.

4.Data Isolation

DBMS allow to view or read only files from different system at same time but it do not allow to write or update at same time because it will create error or wrong calculation while updating files. Multiple users can not update or modify files or data from system at same time.

5. Consistency and integrity

Data values must be meet all the requirement to store in database. This will checked to ensure that they fall within a specified range and are of the current format.

6. Security

It provides more security of data in database.

7. Atomicity

If any problem occur during transaction DBMS take back to origin point of transaction. It perform transaction either all or null.

8. Flexibility and Reliability
Data should flexible to insert, retrieve, update and delete and its data should be reliable because it do not allow to store haphazard data in the database.

9. High availability
Data will easily available when required.

Disadvantages of DBMS

1) Cost of purchasing or developing software is very high.
2) Required trained manpower to manage.
3) Required lots of hardware resources for sharing data.
4) Cost of maintenance of software is high.

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