21. Which of the following is not a property of transactions?
- Atomicity
- Isolation
- Concurrency
- Durability
Answer : C Explanation: None
22. For what purpose the DML is provided?
- Addition of new structure in the database
- Manipulation & processing of the database
- Definition of the physical structure of the database system
- All of the above
Answer : B Explanation: Manipulation & processing of the database. The term “DML” refers to the data manipulation language, which is commonly used to perform basic operations such as insert data, delete, and update data in a database. So option B is correct.
23. Which of the following is not a database object?
- Relationships
- Tables
- Reports
- Queries
Answer : A Explanation: Relationships is not a database object.
24. The users who use the easy-to-use menu are called:
- Sophisticated end users
- Stand-alone users
- Casual end users
- Naive users
Answer : D Explanation: 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.
- Where, having
- Group by, having
- Having, where
- Group by, where
Answer : C Explanation: Correct answer is Having, 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.
- CHECK, FOREIGN KEY
- DELETE, FOREIGN KEY
- CHECK, PRIMARY KEY
- PRIMARY KEY, FOREIGN KEY
Answer : A Explanation: Constraint checking can be disabled on existing CHECK and FOREIGN KEY constraints so that any data you modify or add to the table is not checked against the constraint.
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?
- A is a candidate key
- A is a primary key
- A is not a candidate key
- Both Option (A) & (B)
Answer : C Explanation: None.
28. Which of the following is a concurrency control protocol?
- Locked-based protocol
- Timestamp ordering protocol
- Two-phase locking protocol
- All
Answer : D Explanation: All of the above are concurrency control protocol.
29. Which of the following is a reason to model data?
- Understand each user’s perspective of data
- Understand the data itself irrespective of the physical representation
- Understand the use of data across application areas
- All of the mentioned
Answer : D Explanation: None
30. The term “Data independence” refers to_________
- Data is defined separately and not included in the programs
- Programs are not dependent on the logical attributes of the data
- Programs are not dependent on the physical attributes of the data
- Both Option B & C
Answer : D Explanation: The term “Data independence” refers that the program should not be dependent on either the logical attributes of data or physical attributes of data and hence we can say that option D is correct.
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