3. What is database?
A database is a collection of information that is organized so that it
can easily be accessed, managed, and updated. In one view,
databases can be classified according to types of content:
bibliographic, full-text, numeric, and images.
A database is a logically coherent collection of data with some
inherent meaning, representing some aspect of real world and
which is designed, built and populated with data for a specific
purpose.
5. Why is DBMS?
Ordinary file system has a number of major drawbacks:
1. Data redundancy and inconsistency
- Multiple file formats, duplication of information in different files.
2. Difficulty in accessing data
- Need to write a new program to carry out each new task
3. Data isolation
-Multiple files and formats
4. Atomicity problems
- Failures may leave database in an inconsistent state with
partial updates carried out.
5. Concurrent-access anomalies
- Needed for system performance and usability
