Database Online Test

[Note : pass marks >= 70% ]


1. the advantages of DBMS?
  1. Unauthorised access is restricted
  2. Difficult in accessing data
  3. none.

2. disadvantage in File Processing System?
  1. Data isolation
  2. Security Problems
  3. All

3. Physical level of data abstraction?
  1. The lowest level of abstraction describes how data are stored
  2. The highest level of abstraction describes only part of entire database
  3. none

4. integrity rules in Database
  1. Entity Integrity: States that "Primary key cannot have NULL value"
  2. Referential Integrity: States that "Foreign Key can be either a NULL value or should be Primary Key value of other relation
  3. All

5.What is Data Independence?
  1. The ability to modify the schema definition in one level should not affect the schema definition in the next higher level
  2. Two types of Data Independence: Physical and Logical Data Independence
  3. All

6. What is a view? How it is related to data independence?
  1. A virtual table
  2. Growth and restructuring of base tables is not reflected in views
  3. All

7. What is Data Model?
  1. A collection of conceptual tools for describing data, data relationships data semantics and constraints
  2. It is a 'thing' in the real world with an independent existence
  3. none

8. What is an Entity set?
  1. It is a collection of all entities of particular entity type in the database
  2. It is a 'thing' in the real world with an independent existence
  3. ALL





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