1.0 Introduction
Database system developed because of the need to store large amount of data and retrieve that data quickly and accurately for example, a University abrary stores details about the books held and loans taken out by student. Not very long ago this information about the books and loads might have been stored in a box card index, nowadays, only a few decades later, student are able to view their loans online and see if a book is available and reserve it. The abrary staff can quickly access statistics on overdue books, popular books which never have the shelves.
Another example is a company that accepts customer orders for instance, orders for spare parts for electrical goods. Originally orders might have been created when a customer telephone the company to place the order. If information about the customer already existed in a paper file then his/her details would be requested and recorded. An order form would have been filled in and copies: one copy being stored in a filing cabinet, the other, information on stock held would need to be accessed.
Eventually, the order entry system was computerized so that by the 1960’s the data about customers and orders might have been stored in a computer file- a magnetic tape file and then later magnetic desk. These files were processed by computer programs. Other applications programs were used which could create invoices, orders to suppliers and so on. Although different application software would at times require similar data, the data would be kept on different files. In both types of system, the paper one and the files system, processing was slow and problems of inconsistencies of data could easily develop. The introduction of shaved files. Whereby different applications shaved some of the same files, solved some of the problems described earlier, and was good for providing routine data. For example, a customer order application and an invoicing application might use both the customer