Disadvantages of File Processing System
- Data Redundancy and Inconsistency
- Data Isolation
- Integrity Problem
- Program Data Dependency
- Atomicity Problem
- Security Problem
- Program Maintenance
1) Data Redundancy and Inconsistency:
In file processing system, the same data may be duplicated in several files. Suppose there are two files "students" and the "library". The file "students" contains the role number, name, address, telephone number, and other details of all students in acollege. The file "library" contains the room number and name of those students who getabook from the library along with the information about the rented books. The data of one student appears in two files. This is known as data redundancy. Redundancy causes higher storage.
This situation can also result in data inconsistency. Inconsistency means that two files may contain different data of the same student. For example, if the address of astudent is changed, it must be changed in both fles. There isapossibility that it is changed in the "students" file and not from the "library" file. The data because inconsistent in that situation.
2) Data Isolation:
The data in the file processing system is stored in various files. It becomes very difficult to write new application programs to retrieve the appropriate data. Suppose that student emails are stored in the "students" file and fee information is stored in the "fee" file. The data from both files are required to send an email message to informa student that the date for fee payment is over. Inafile processing system, it is difficult to generate such type of list from multiple files.
3) Integrity problems
Integrity means reliability and accuracy of data. The stored data must satisfy certain types of consistency constraints. For example, Roll No and Marks of students should beanumeric value. It is very difficult to apply these constraints on files in the file processing system.
4) Program data dependency
Program data dependency isarelationship between data in files and the program required to update and maintain the files. Application programs are developed according toaparticular file format in the file processing system. If the format of the file is changed the application program also needs to be changed accordingly. For example, if there isachange in the length of the postal code, it requiresa change in the program. The changes may be costly to implement.
5) Atomicity problem
An operation on data may consist of different steps.Acollection of all steps required to completeaprocess is known asatransaction. The atomicity means that either one transaction should take place asawhole or it should not take place at all. Supposea user wants to transfer money from accountAto account B. This process consists of two steps:
- Deduct the money from account A
- Add the money to account B Suppose that the system fails when the computer has performed the first step, It means that the amount has been deducted from accountAbut has not been addéd to account B. This situation can make data inconsistent. File processing system does not provide the facility to ensure the atomicity of data.
6) Security problems
File processing system does not provide adequate security on data. In some situations, it is required to provide different types of access to data for different users. For example,adata entry operator should only be allowed to enter dåta. The chairman of the organization should be able to access or delete the data completely. Such types of security options are not available in file processing system.
7) Program maintenance
The program developed in file processing system is difficult to maintain. Most of the budget may be spent on maintenance. It makes it difficult to develop new applications.