21. Which of the following is not a property of transactions?

1. Atomicity
2. Isolation
3. Concurrency
4. Durability

22. For what purpose the DML is provided?

1. Addition of new structure in the database
2. Manipulation & processing of the database
3. Definition of the physical structure of the database system
4. All of the above

23. Which of the following is not a database object?

1. Relationships
2. Tables
3. Reports
4. Queries

24. The users who use the easy-to-use menu are called:

1. Sophisticated end users
2. Stand-alone users
3. Casual end users
4. Naive users

25. Aggregate functions can be used in the select list or the_______clause of a select statement or subquery. They cannot be used in a ______ clause.

1. Where, having
2. Group by, having
3. Having, where
4. Group by, where

26. Constraint checking can be disabled on existing _________ and ____________ constraints so that any data you modify or add to the table is not checked against the constraint.

1. CHECK, FOREIGN KEY
2. DELETE, FOREIGN KEY
3. CHECK, PRIMARY KEY
4. PRIMARY KEY, FOREIGN KEY

27. An instance of relational schema R (A, B, C) has distinct values of A including NULL values. Which one of the following is true?

1. A is a candidate key
2. A is a primary key
3. A is not a candidate key
4. Both Option (A) & (B)

28. Which of the following is a concurrency control protocol?

1. Locked-based protocol
2. Timestamp ordering protocol
3. Two-phase locking protocol
4. All

29. Which of the following is a reason to model data?

1. Understand each user’s perspective of data
2. Understand the data itself irrespective of the physical representation
3. Understand the use of data across application areas
4. All of the mentioned

30. The term “Data independence” refers to_________

1. Data is defined separately and not included in the programs
2. Programs are not dependent on the logical attributes of the data
3. Programs are not dependent on the physical attributes of the data
4. Both Option B & C