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Cs 06
Q2
Ans - - - -
Answer
The difference between file-oriented system and database system can be discussed in the context of
following: 1. Data Independence : Data Independence can be defined as application flexibility to change in storage
structure and access strategy. Both the database and the user program can be modified independently of
each other. In file oriented approach, applications are data dependents and data files depends of application
programs. If a data file is to be added to a master data file, all such programs that access the master file
would have to be modified to allow this new file to be added to Master record. Hence program become
dependent on data files and data files become dependent on programs. In database system this can be done
independently.
2. Data Redundancy : In file-oriented system, each application has it's own private files. Due to
decentralization of data, the file oriented system leads to uncontrolled duplication of data. This can lead to
redundancy in stored data, which result in wastage of storage space. In database oriented approach data
can be stored centrally at a single storage location with controlled redundancy under DBMS, which saves
space and eliminates redundancy.
3. Security : In DBMS, DBA can ensure access to the database and can define access right for any user to
any data items or a subset of the database. It is very difficult to implement security mechanisms in a fileoriented system.
4. Centralised Control : - With central control of database, DBA can ensure standards are followed in the
representation of data. In file -oriented system this is controlled by application programs.
5. Data Integrity :- It ensures that the data in the database is accurate. In DBMS, centralised control of
database helps maintain integrity, and permits the DBA to define validation procedures to be carried out
whenever any update operation is attempted against data. These update inculdes modification, creation and
deletion.
Q no
4
Answer
The advantage of Index-sequential file is that you can search the file more quickly. If you know the key
value that you want, you can use one of the relatively fast searches.
Allows both sequential processing and individual record retrieval through the index.
The disadvantage is that when you insert, you need to rewrite at least everything after the insertion point,
which makes inserts very expensive unless they are done at the end of the file.