File Processing System (MIS 24.05.2021)

File Processing System.

A file processing system is a collection of files and programs that access or modify these files. In a file processing system, the record is maintained in different files. All files are separate and not linked with each other. It is an old method of record keeping.

 

In daily life, we come across various needs to store data. It can be maintaining daily household bills, bank account details, salary details, payment details, student information, student reports, books in the library, etc. How it will be recorded in one place so that we can get it back when required? It should be recorded in such a way that

1.               Should be able to get the data any point in time latter.

2.               Should be able to add details to it whenever required.

3.               Should be able to modify stored information, as needed.

4.               Should also be able to delete them.

 

In the traditional approach, before to computer, all pieces of information were stored in papers. When we need information, we used to search through the papers. If we know a particular date or category of information we are searching for, we go to that particular session in the papers. When we want to update or delete some data, we search for it and modify them or strike off them. If the data is limited, then all these tasks are easy. Imagine library information or information about a student in school, or a banking system! How do we search for single required data in papers? It is a never-ending task! Yes, Computers solved our problems.

 

A file processing system is a collection of programs that store and manage files in computer hard-disk. File processing system has more data redundancy, less data redundancy in DBMS. File processing system provides less flexibility in accessing data, whereas DBMS has more flexibility in accessing data.

 

Traditional File Processing System

File processing systems was an early attempt to computerize the manual filing system that we are all familiar with. A file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. File systems may use a storage device such as a hard disk and involve maintaining the physical location of the files.

 

The manual filing system works well when the number of items to be stored is small. It even works quite adequately when there are large numbers of items and we have only to store and retrieve them. However, the manual filing system breaks down when we have to cross-reference or process the information in the files. For example, a typical real estate agent’s office might have a separate file for each property for sale or rent, each potential buyer and renter, and each member of staff.

Clearly the manual system is inadequate for this type of work. The file-based system was developed in response to the needs of industry for more efficient data access. In early processing systems, an organization’s information was stored as groups of records in separate files.

 

In the traditional approach, we used to store information in flat files which are maintained by the file system under the operating system’s control. Here, flat files are files containing records having no structured relationship among them. The file handling which we learn under C/C ++ is the example of file processing system.

 

Characteristics of File Processing System

Here is the list of some important characteristics of file processing system:

1. It is a group of files storing data of an organization.

2. Each file is independent from one another.

3. Each file is called a flat file.

4. Each file contained and processed information for one specific function, such as accounting or inventory.

5. Files are designed by using programs written in programming languages such as COBOL, C, C++.

6. The physical implementation and access procedures are written into database application; therefore, physical changes resulted in intensive rework on the part of the programmer.

7. As systems became more complex, file processing systems offered little flexibility, presented many limitations, and were difficult to maintain. 

 

Limitations of the File Processing System I File-Based Approach

There are following problems associated with the File Based Approach:

1. Separated and Isolated Data: To make a decision, a user might need data from two separate files. First, the files were evaluated by analysts and programmers to determine the specific data required from each file and the relationships between the data and then applications could be written in a programming language to process and extract the needed data. Imagine the work involved if data from several files was needed.

 

2. Duplication of data: Often the same information is stored in more than one file. Uncontrolled duplication of data is not required for several reasons, such as:

• Duplication is wasteful. It costs time and money to enter the data more than once

• It takes up additional storage space, again with associated costs.

• Duplication can lead to loss of data integrity; in other words, the data is no longer consistent.

 

3. Data Dependence: In file processing systems, files and records were described by specific physical formats that were coded into the application program by programmers. If the format of a certain record was changed, the code in each file containing that format must be updated. Furthermore, instructions for data storage and access were written into the application’s code. Therefore, changes in storage structure or access methods could greatly affect the processing or results of an application.

 

4. Difficulty in representing data from the user’s view: To create useful applications for the user, often data from various files must be combined. In file processing it was difficult to determine relationships between isolated data in order to meet user requirements.

 

5. Data Inflexibility: Program-data inter dependency and data isolation, limited the flexibility of file processing systems in providing users with ad-hoc information requests

 

6. Incompatible file formats: As the structure of files is embedded in the application programs, the structures are dependent on the application programming language. For example, the structure of a file generated by a COBOL program may be different from the structure of a file generated by a ‘C’ program. The direct incompatibility of such files makes them difficult to process jointly.

 

7. Data Security. The security of data is low in file-based system because, the data is maintained in the flat file(s) is easily accessible. For Example: Consider the Banking System. The Customer Transaction file has details about the total available balance of all customers. A Customer wants information about his account balance. In a file system it is difficult to give the Customer access to only his data in the· file. Thus, enforcing security constraints for the entire file or for certain data items are difficult.

 

8. Transactional Problems. The File based system approach does not satisfy transaction properties like Atomicity, Consistency, Isolation and Durability properties commonly known as ACID properties.

 

For example: Suppose, in a banking system, a transaction that transfers Rs. 1000 from account A to account B with initial values of A and B being Rs. 5000 and Rs. 10000 respectively. If a system crash occurred after the withdrawal of Rs. 1000 from account A, but before depositing of amount in account B, it will result an inconsistent state of the system. It means that the transactions should not execute partially but wholly. This concept is known as Atomicity of a transaction (either 0% or 100% of transaction). It is difficult to achieve this property in a file-based system.

 

9. Concurrency problems. When multiple users access the same piece of data at same interval of time then it is called as concurrency of the system. When two or more users read the data simultaneously there is no problem, but when they like to update a file simultaneously, it may result in a problem.

 

10. Poor data modelling of real world. The file-based system is not able to represent the complex data and interfile relationships, which results poor data modelling properties.