REVIEW OF THE DATABASE CONCEPTS *IMPORTANT*

DATABASE CONCEPTS

Database

Every organization has to deal with different types of data depending upon the volume of transactions. These transactions may be of different nature. There are the following stages involved while dealing with the data.

1. Receive
2. Storing
3. Retrieval
4. Processing 
5. Distribution

Let us try to understand the concept of Data Base in the following reference. Consider an example of large manufacturing organization. The organization has various departments mentioned as under:

• Sales Department

• Production Department

• Purchase Department

• Stores Department

• Accounts Department

• Management

All the departments are linked with each other in one way or another. If the organization has computerized Data Base, the process of storing, retrieval, processing and distribution of information becomes very easier. Sitting in Sales Department, one can obtain the information of total purchases through the computer in no time. Management obtains a clear picture of the performance of the organization.

A collection of logically related data stored together, is called database.

DATABASE

Database contains various records and fields. A column in the table can be referred to as field and a row can be called as record.

Each row contains complete information about one item.

What is a Database?

Database contains various records and fields. A column in the table can be referred to as a field and a row can be called as a record.

Purpose of Database

In the present day environment and due to computerization in various institutions and organizations, the complex activities are being performed on computers in the form of databases and other data. Manual process has been converted into computerized one and need of databases in on increase. The databases are being managed due to one reason or other which have been explained below.

1. Data Redundancy Reduces

Databases reduce redundancy to a maximum extent. Data redundancy is a sort of duplication of data. In manual systems, the work is done. For example, in a school, manual database may be there. A student's address may be recorded in Fees Section, Library and Administration Section. If a student's address is changed and the Administration Section does not inform the Fees Section or Library, his old address is continued to be recorded in Fees Section and Library. If computerized database is maintained, the change in all files is recorded automatically. Therefore, computerized database eliminates inconsistency.

2. Sharing of Data is Possible 

Databases can be shared when the data is centralized. If LAN system has been installed in the institution, data can be shared by different employees and workers by using their own password. A lot of time is saved in going here and there to collect the data.

3. Security Feature

A Data Base Administrator (DBA) looks after the computerized environment. He has the complete control over databases. He ensures that the database is secured in computer and there is no unauthorized access to the database. He has the supervisory rights and provides the user rights to the user. A password is allotted to each user and by using his own password, the user can access to the database. An unauthorized user cannot have access to the data.

4. Integrity is Possible

A standard is maintained in the database. For example, if you want to enter the date of 29 February in the year 2002, it will not be valid date and the database will not accept it. Similarly, if you have set maximum marks of a subject as 100, you cannot enter more than 100 marks in marks obtained cell. Inbuilt system is maintained which will accept marks only less than 100.

5. Easy Storage

The database in computerized environment can be stored on hard disk or floppies. It is very easy to take backup of the database. It is possible by learning few commands. Moreover, the data is in compressed form and manual file work is not be done. Computerized database saves lot of storage space.

Operations on Database

Various types of operations can be done on the database which have been mentioned below.

• Insert Data : The data can be inserted into the database by creating a table or multiple tables.
• Reproduction of Information : The stored data can be produced as output.
• Modification : The data inserted into the database can be modified according to the needs.
• Editing : The existing information in the database can be edited to rectify the errors or for other purposes.
• Deletion : The unnecessary data in the database can be deleted.
• Sequence : The data in the database can be arranged in sequence either in ascending order or in descending order or any other criteria.