Disadvantages of file processing system over database management system, List down the disadvantages of file processing systems.
Disadvantages of File Processing System
a) Data redundancy and inconsistency
File
processing system leads to the usage of many copies of same data. This is data
redundancy. If we need to change any of the data, then we need to change the
data at all copies. If not, this will lead to inconsistency.
For
example, let us assume a file for storing addresses of students. If we make
three copies of the address file and store them in three different computers, we
say that the data is redundant. If suppose one want to change the address of
any students, then the change should be made at all the three computers failing
which leads to inconsistent data.
b) Difficulty in accessing data
In a file
processing system, to access data differently we need to have different
programs.
For example, if
you want to access student names from a file, we need a program that does the job.
If you want to view only address of all students from a specific city, then we
need different program that does the required job. This list goes endless. Hence,
it is difficult to access data.
c) Data isolation
Files
are stored in different locations, different formats. Thus they are isolated.
For
example, one location the student data may be stored in .txt format. In other location, the same file may be stored in .doc format.
d) Integrity problems
Integrity
problem arises when the database fails to satisfy certain integrity conditions.
For
example, the phone number cannot be longer than 10 digits, bank balance should
not go below 1000 etc. The actual problem arises when we would like to include
new such conditions with the existing database. It is hard to make those
changes.
e) Atomicity problems
The
database must be in a consistent state in spite of failures.
For
example, let us suppose that you have a savings account with the balance 5000 and
a loan account with an outstanding of 3000. This is the old consistent state. Now you would like to transfer 500
to your loan account. If this transaction is successful, then your savings
balance should be 4500 and loan outstanding should be 2500. This is the new consistent state. Suppose
a failure occurs during this transaction, the database must be in any one of
the 2 consistent states mentioned above.
It
is hard to maintain atomicity in file processing system due to data redundancy,
data isolation etc.
f) Concurrent access anomalies
Simultaneous
access of a data item should be handled carefully.
For
example, if only one ticket is there and two customers are trying to book the
ticket simultaneously, the ticket should be allotted to any one customer.
It
is difficult to handle in file processing system due to the fact of data
isolation, redundancy etc.
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