File processing System

       A file processing system is a collection of files and program. Programs access and modify the files. In file processing system records in one file are not related to the records in any other file. New files are added as new information needs to be stored in the system. To handle limited number of files and data file processing system is best but to handle large system it becomes difficult.

 Disadvantages of file processing system:-

1.   Data redundancy:-

                          In a file processing system some data may be duplicated in a several files there is no method to validate the insertion of a data in the system. File system does not validate the insertion of any kind of data in the system with previously stored data in the file. For example there are two files student and library. The file of student contain student data such as roll no, name of the student, address and telephone number etc of all student in a college. The library file contain roll no and name of the student who takes a book from library and information about the rented books. The data of a student appeared in two files. This is known as a data redundancy. The duplication of a data cause higher storage and lead to confusion and misleading of data of any person in the system. Data redundancy cause another issue if we want to update data of the system, it might be possible to update data in one file and leaving the other record same in the file this situation cause many problem.

2.   Data inconsistency:-

                       Data redundancy leads to data inconsistency. Data inconsistency means that two files of a same person may contain different data. For example two files student file and library file, if the address of a student is change and data is updated correctly in student file not in library file the data become inconsistent in this situation because there is a no proper management of files which has contain same copy of data.

3.   Program data dependency:-

                                       Data dependency is a relationship between data in file and program required to update and maintain the file. In the files data are stored in a specific format. Application program are developed according to a particular file format in a file processing system. If the file format is change then application program also need to be change accordingly. For example if postal code length is change, it require change in the application program and if change in storage structure it effect all places where this file is used we have to change it program entirely. The change may be costly to implement.

4.   Data isolation:-

                        In file processing system information is stored in different files. If we want to write a report we need information about the data that is stored in different files. For retrieving data from different files in the system need an application program. It becomes very difficult to write new application program to retrieve suitable data. Before writing the program we need to know the format of each file etc. For example to generate a single report of a student, his study report, his library book details, hostel information and fee information all these information are stored in different files. In file processing system it is very difficult to generate a report from different files.

5.   Integrity problem:-

                             Integrity means accuracy of a data. Data stored in a system must satisfy the certain type of constrains. For example roll no always a numeric value. This required a program to maintain integrity in the system. In file processing system there is no direct checking facility. Integrity in file system is very difficult.

6.   Security:-

               A security on data in a file processing system becomes very difficult. For example data entry operator should only be allowed to enter data. Password on file to access certain type of data in a system becomes difficult. The chairman of an organization should be able to enter or delete the data completely. Such types of security options are not available in the file processing system.

7.   Atomicity problem:-

                              Atomicity means that either one transaction should take place as a whole or should not take place at all. Partial completion of any transaction leads to incorrect data in the system. File processing system does not provide atomicity facility for data.

8.   Program maintenance:-

                                Programs in file processing system are difficult to maintain. Cost of maintenance is very high. To develop new application is very difficult.