Data Redundancy and Inconsistency
In file processing system, the same data may be duplicated in several files. For example, there are two files “Students” and “Library”. The file “Students” contains the Roll No, name, address and telephone number and other details of all students in a college. The file “Library” contains the Roll No and name of those students who get a book 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. This 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 a student is changed, it must be changed in both files. There is a possibility that it is changed in the “Students” file and not from “Library” file. In this case, the data of the student becomes inconsistent.
