Q. Why would you choose a database system instead of simply storing data in operating system file? Define at a base concept in details.
Sol. Advantages of Database over File System:
1. Controlling redundancy: The redundancy in storing the same data multiple time leads to several problems. In database approach, the views of different use of groups are integrated during database design.
2. Restricting unauthorized access: When multiple users share a database, it is likely that some users will not be authorized to access all information in the database. The DBMS provides security and authorization suggestions which the DBA uses.
3. Providing persistent storage: Database can be used to provide persistent storage for program objects and data structures.
4. Permitting inferencing and actions using rules: Some systems provide capabilities for defining deduction rules for inferencing new information from ser database facts.
5. Provides multiple user interfaces.
6. Representing complex relationships among data.
7. Enforcing constraints: A DBMS should provide capabilities for defining and enforcing these constraints.
8. Providing backup and recovery: A DBMS must provide facilities for recovering from hardware and software families.
Disadvantages: These are a few situations in which such a system may involve unnecessary overhead costs. The costs are due to:
1. High initial investments
2. Generality that a DBMS provides
3. Overhead for providing security, etc.
Hence, it may be more desirable to use regular files when
(i) The database and applications are simple, well defined and not expected to change.
(ii) Multiple user access is not required.