Database Concepts

Introduction

A database is an organized collection of data, generally stored and accessed electronically from a computer system. The term "database" is also used to refer to any of the DBMS, the database system or an application associated with the database. Because of the close relationship between them, the term "database" is often used casually to refer to both a database and the DBMS used to manipulate it. A school class register is a database where names are arranged alphabetically. Databases have been around since people started recording things. Here we tend to focus on electronic ones.

Data

Data are raw facts stored in a computer. A data may contain any character, text, word or a number.

Example : 600006, DPI Campus, SCERT, Chennai, College Road

Information

Information is formatted data, which allows to be utilized in a significant way.

Example

SCERT

College Road

DPI Campus

Chennai 600006

As  you  can  see from the example above, data appears as a set of words and numbers. However, when the data is processed, organized and formatted, it gives a meaningful information about the SCERT institution contact address.

Database

Database is a repository collection of related data organized in a way that data can be easily accessed, managed and updated. Database can be a software or hardware based, with one sole purpose of storing data.

DataBase Management System (DBMS)

A DBMS is a software that allows us to create, define and manipulate database, allowing users to store, process and analyze data easily. DBMS provides us with an interface or a tool, to perform various operations to create a database, storing of data and for updating data, etc. DBMS also provides protection and security to the databases. It also maintains data consistency in case of multiple users.

Examples of DBMS softwares are : Foxpro, dbase.

Characteristics of Database Management System

1. Data stored into Tables

Data is never directly stored into the database. Data is stored into tables, created inside the database. DBMS also allows to have relationship between tables which makes the data more meaningful and connected.

2. Reduced Redundancy

In the modern world hard drives are very cheap, but earlier when hard drives were too expensive, unnecessary repetition of data in database was a big problem But DBMS follows Normalisation which divides the data in such a way that repetition is minimum.

3.Data Consistency

On live data, it is being continuously updated and added, maintaining the consistency of data can become a challenge.  But DBMS handles it by itself.

4. Support Multiple user and Concurrent Access

DBMS allows multiple users to work on it(update, insert, delete data) at the same time and still manages to maintain the data consistency.

5.Query Language

DBMS provides users with a simple query language, using which data can be easily fetched, inserted, deleted and updated in a database.

6. Security

The DBMS also takes care of the security of data, protecting the data from unauthorized access. In a typical DBMS, we can create user accounts with different access permissions, using which we can easily secure our data by restricting user access.

7. DBMS Supports Transactions

It allows us to better handle and manage data integrity in real world applications where multi-threading is extensively used.

Advantages of DBMS

·        Segregation of application program

·        Minimal data duplication or Data Redundancy

·        Easy retrieval of data using the Query Language

·        Reduced development time and maintenance

Components of DBMS

The Database Management System can be divided into five major components as follows:

1.Hardware

2.Software

3.Data

4 . Procedures / Methods

5.Database Access Languages

Hardware: The computer, hard disk, I/O channels for data, and any other physical component involved in storage of data

Software: This main component is a program that controls everything. The DBMS software is capable of understanding the Database Access Languages and interprets into database commands for execution.

Data: It is that resource for which DBMS is designed. DBMS creation is to store and utilize data.

Procedures/Methods: They are general instructions to use a database management system such as installation of DBMS, manage databases to take backups, report generation, etc.

DataBase Access Languages: They are the languages used to write commands to access, insert, update and delete data stored in any database.

Examples of popular DBMS: Dbase, FoxPro