1000+ DBMS MCQ for GATE [Solved]

1. Which one is true statement :
A. With finer degree of granularity of locking a high degree of concurrency is possible.
B. Locking prevents non-serializable schedules.
C. Locking cannot take place at field level.
D. An exclusive lock on data item X is granted even if a shared lock is already held on X.
Answer : A

2. Isolation of the transactions is ensured by
A. Transaction management
B. Application programmer
C. Concurrency control
D. Recovery management
Answer : C

3. The division operator divides a dividend A of degree m+n by a divisor relation B of degree n and produces a result of degree
A. m - 1
B. m + 1
C. m * m
D. m
Answer : D

4. If an entity can belong to only one lower level entity then the constraint is
A. disjoint
B. partial
C. overlapping
D. single
Answer : B

5. In SQL, testing whether a subquery is empty is done using
A. DISTINCT
B. UNIQUE
C. NULL
D. EXISTS
Answer : D

6. For correct behaviour during recovery, undo and redo operation must be
A. Commutative
B. Associative
C. idempotent
D. distributive
Answer : C

7. A transaction is in state after the final statement has been executed.
A. partially committed
B. active
C. committed
D. none of the above
Answer : C

8. Shadow paging has
A. no redo
B. no undo
C. redo but no undo
D. neither redo nor undo
Answer : A

9. Which of the following constitutes a basic set of operations for manipulating relational data?
A. Predicate calculus
B. Relational calculus
C. Relational algebra
D. SQL
Answer : C

10. A logical schema
A. is the entire database
B. Describes how data is actually stored on disk.
C. is a standard way of organizing information into accessible parts.
D. All of the above
Answer : C

11. The graphical representation of a query is .
A. B-Tree
B. graph
C. Query Tree
D. directed graph
Answer : C

12. The data models defined by ANSI/SPARC architecture are
A. Conceptual, physical and internal
B. Conceptual, view and external
C. Logical, physical and internal
D. Logical, physical and view
Answer : D

13. A relational database developer refers to a record as
A. an attribute
B. a tuple
C. a criteria
D. a relation
Answer : B

14. E-R Modeling is achieved by using ____ diagrams
A. DFD
B. Flowcharts
C. Gantt Charts
D. E-R
Answer : D

15. The relational model is based on the concept that data is organized and stored in two-dimensional tables called ______
A. Fields
B. Records
C. Relations
D. Keys
Answer : C

16. Which one is correct statement?
Logical data independence provides following without changing application programs:
(i) Changes in access methods.
(ii) Adding new entities in database
(iii) Splitting an existing record into two or more records
(iv) C
A. (i) and (ii)
B. (iv) only
C. (i) and (iv)
D. (ii) and (iii)
Answer : D

17. A _____ is used to define overall design of the database
A. code
B. data definition language
C. application program
D. schema
Answer : D

18. Which of the following addressing modes permits relocation without any change over in the code?
A. Indirect addressing
B. Indexed addressing
C. PC relative addressing
D. Base register addressing
Answer : B

19. ____specifies a search condition for a group or an aggregate.
A. GROUP BY Clause
B. HAVING Clause
C. FROM Clause
D. WHERE Clause
Answer : B

20. In E-R Diagram total participation is represented by
A. Double lines
B. Single line
C. Dashed lines
D. Triangle
Answer : A

21. The _______ is a set of programs to use and / or modify this data.
A. DBMS
B. System
C. Program
D. Software
Answer : A

22. SQL server stores index information in the _____system table
A. system indexes
B. syst indexes
C. sys indexes
D. sysind
Answer : C

23. Which of the following is not a characteristic of a relational database model?
A. Table
B. Tree like structure
C. Complex logical relationship
D. Records
Answer : B

24. The clause alter table in SQL can be used to
A. add an attribute
B. delete an attribute
C. alter the default values of an attribute
D. all of the above
Answer : D

25. The concept of mapping of ______ entity types is the concept in which the for each strong entity type E in the ER schema, create a relation R that includes all the simple attributes of E.
A. Regular
B. Irregular
C. None
D. Weak
Answer : A

26. An advantage of views is
A. Data security
B. Derived columns
C. Hiding of complex queries
D. All of the above
Answer : A

27. The fact that information in the data warehouse changes far less often and may be regarded as non-real-time with periodic updating; This implies that data warehouses are _______
A. Volatile
B. Non - Volatile
C. Logical
D. Physical
Answer : B

28. When an E-R diagram is mapped to tables, the representation is redundant for
A. weak entity sets
B. weak relationship sets
C. strong entity sets
D. strong relationship sets
Answer : B

29. The data in the database at a particular moment of time is called the _______
A. Snapshot
B. Dynaset
C. Stateless
D. Stateful
Answer : A

30. In multiple granularity of locks SIX lock is compatible with
A. IX
B. IS
C. S
D. SIX
Answer : B

31. ____ table store information about database or about the system.
A. SQL
B. System
C. Nested
D. None of these
Answer : B

32. It is an abstraction through which relationships are treated as higher level entities
A. Generalization.
B. Specialization.
C. Aggregation.
D. Inheritance.
Answer : C

33. ______ keyword is used to find the number of values in a column.
A. TOTAL
B. ADD
C. COUNT
D. SUM
Answer : C

34. Processed data is called _____
A. Raw data
B. Source
C. Information
D. Useful data
Answer : C

35. Employees in a company are each assigned their own office, i.e. for each employee there exists a unique office and for each office there exists a unique employee; This statement is an example of ____ type of relation.
A. 1:1
B. 1: Many
C. Many: One
D. Many : Many
Answer : A

36. A DBMS is a ____ user if at most one user can use the system and is mostly restricted to personal computer systems.
A. None
B. Multi
C. Single
D. Concurrent
Answer : C

37. Which of the following relational algebraic operations is not from set theory?
A. Union
B. Intersection
C. Cartesian Product
D. Select
Answer : D

38. An outstanding functionality of SQL is its support for automatic_____ to the target data.
A. programming
B. navigation
C. functioning
D. notification
Answer : B

39. Relational Algebra is
A. Data Definition Language .
B. Meta Language
C. Procedural query Language
D. None of the above
Answer : C

40. Which of the following is a reason to model data?
A. Understand each user's perspective of data
B. Understand the data itself irrespective of the physical representation
C. Understand the use of data across application areas
D. All of the above
Answer : D

41. Change Staff table by removing default of Assistant for position column
A. ALTER TABLE Staff ALTER position DROP DEFAULT;
B. ALTER TABLE Staff ALTER position DEFAULT;
C. ALTER TABLE Staff ALTER DROP DEFAULT;
D. MODIFY Staff ALTER position DROP DEFAULT;
Answer : A

42. Dependency preservation is not guaranteed in
A. BCNF
B. 3NF
C. PJNF
D. DKNF
Answer : A

43. Which of the following aggregate functions does not ignore nulls in its results?.
A. COUNT .
B. COUNT (*)
C. MAX
D. MIN
Answer : B

44. Which of the following is not a property of transactions?
A. Atomicity
B. Concurrency
C. Isolation
D. Durability
Answer : B

45. If a transaction T has obtained an exclusive lock on item Q, then T can
A. read Q
B. write Q
C. both read and write Q
D. write Q but not read Q
Answer : C

46. In an ER model,_____ is described in the database by storing its data.
A. Entity
B. Attribute
C. Relationship
D. Notation
Answer : A

47. In an E-R, Y is the dominant entity and X is a subordinate entity. Then which of the following is incorrect :
A. Operationally, if Y is deleted, so is X
B. existence is dependent on Y.
C. Operationally, if X is delete, so is Y.
D. Operationally, if X is deleted, & remains the same.
Answer : C

48. Which of the following ensures the atomicity of the transaction?
A. Transaction management component of DBMS
B. Application Programmer
C. Concurrency control component of DBMS
D. Recovery management component of DBMS
Answer : A

49. A _____ is a logical unit of database processing that includes one or more data access operations that can include insertion, deletion, modification or retrieval operations.
A. Database
B. Data
C. Transaction
D. Record
Answer : C

50. What are the desirable properties of a decomposition
A. Partition constraint.
B. Dependency preservation.
C. Redundancy.
D. Security.
Answer : B