Скачать или смотреть 1. Data Redundancy and InconsistecyIn file processing system,

1. Data Redundancy and Inconsistecy
In file processing system, the same data may be duplicated in several files. Supposethere are two hiles Students and Library The file Students" contains the Roll No,name,address and telephone number and other details ot all students in a college.The file"Library"conta.ns the Roll No and name of those stadents « ho get a book trom library along with theintormation aboul the rented books The data of one student appears in two files. This isknown as dahttedundaus This redundanes canses hither storage
11situation cah also nsult m0.1sterInconsisteney means that two files020may contam diterent data of the same stadent tor example it the address of a student ischansed,it mast be changed in both biles. There is a pwstbility that it ischanged in theStudents the and not trom lbrary tle The dats becomes inconsistent in this situation.
2. Data Isolation
The dala in hle processing system is stored in various files. It becomes very ditficult towrte new apphiation programs to retrieve the appropriate data Suppose that student emailsare stored in Students" tile and fee intormation is stored in Tee file. The data from bothfiles is required to send an email message to inform a student that the date for fee payment isover. In tile 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 certaintypes of consistency constrains. For example, Roll No and Marks of students should benumeric value.