Why the Advent of Databases-1

I am writing a book on Databases. In the current blog, I will give you every Friday morning BDT time, small excerpts on Databases from my book in order to brush up on the subject. My eBook on Databases is a copyright in 2015 by me, Rosina S Khan. No part(s) or whole of these excerpts may be used or reproduced in any form whatsoever, without written permission by the author. Here goes the very first post:

Before the advent of databases, organizations stored information using a typical file- processing system. In this system, permanent records were stored in various files and different application programs were written to extract records from, and to add records to, the appropriate files.

File-processing systems have a number of disadvantages. Two of these are outlined as follows:

 

• Data redundancy and inconsistency: Different programmers may write the files and application programs over a passage of time. As a result files may have different structures and the programs may be written in different several programming languages. Also the same information may appear in different files. Data inconsistency results when the same information is updated in one place but not in another place in addition to higher storage and access cost.

• Difficulty in accessing data: Data retrieval may be problematic. Suppose a bank officer needs to find out the list of customers who live in a certain postal code. Such an application program does not exist. There is, however, an application program to generate the list of customers. The data processing department based on the demand of the bank officer has either to generate the list of customers and extract the needed info manually. The other alternative is to write a new application program to meet the demand. Both the alternatives are unsatisfactory. After a week or so, the bank officer needs to trim down the list of customers with bank balances more than Tk50,000. Again the data processing department is left with two alternatives both of which are unsatisfactory. The point here is that file processing systems do not allow data to be retrieved in a convenient and efficient manner.