Relational Database Management Systems

Book Preface

Databases offer a convenient and powerful way to organize information.

Databases are not specific to computers. Examples of non-computerised databases are phone book, dictionaries, almanacs, etc. Databases are designed to offer an organized mechanism for storing, managing and retrieving information. Databases are probably one of the most common uses of computers, and are available on just about every type of computer. There are three main components to any database application:

• A method for entering or editing data — usually data entry screens or import functions
• A data storage mechanism — a way of storing the data on the computer
• A report generator to extract and interpret information from the stored data

Data is collection of raw/ unorganized facts and figures. It simply exists and has no significance beyond its existence. It can exist in any form, usable or not. It is always need to be processed. Raw data may be collection of numbers, characters, images or it can be acquired from many different sources. Data are typically the results of measurements and can be the basis of symbols, graphs, images, or observations of a set of variables. For example, age of students, the height of students, marks of students, blood group students, is generally considered as “data”