Data, Information and the Need for a Database

Every business runs on facts. The name of a customer, the price of a product, the quantity sold on a particular date, the roll number of a student, the balance in a bank account — all of these are examples of data. In this Maharashtra HSC (MSBSHSE) Std XI Information Technology course you will see that almost every computer application, from a shop's billing counter to a school's examination system, is really a tool for storing and working with data.

Data are raw, unprocessed facts and figures that on their own may not carry much meaning. For example, the numbers 72, 85 and 64 are just data. When data are collected, organised and processed so that they become meaningful and useful for taking a decision, they become information. If we are told that 72, 85 and 64 are the marks scored by a student in three subjects and that the student's average is 73.6%, the same numbers now carry meaning — that is information. In short, information is processed data, and the whole purpose of storing data well is to be able to get useful information out of it quickly and accurately.

A database is an organised collection of related data stored in such a way that it can be easily accessed, managed and updated. The word 'organised' is the key idea: the data are not scattered in loose sheets or unrelated files but are arranged in a structured form (most commonly in tables) so that a computer can search, sort and combine them efficiently. A telephone directory, a library catalogue, and a school's list of students with their classes and marks are all everyday examples of databases — collections of related facts kept together in a fixed structure.

Before databases became common, businesses stored data in ordinary computer files — for example, one file for customer details, another for orders, another for payments — handled directly by individual application programs. This file-based approach worked for small amounts of data but created serious problems as data grew, which is exactly the problem a Database Management System is designed to solve, as the next sections explain.