Database Systems MCQ

 Q.1 Which of the following is correct:
(A) a SQL query automatically eliminates duplicates.
(B) SQL permits attribute names to be repeated in the same relation.
(C) a SQL query will not work if there are no indexes on the relations
(D) None of these
Ans: D

Q.2 It is better to use files than a DBMS when there are
(A) Stringent real-time requirements.
(B) Multiple users wish to access the data.
(C) Complex relationships among data.
(D) All of the above.
Ans: B

Q.3 The conceptual model is
(A) dependent on hardware.
(B) dependent on software.
(C) dependent on both hardware and software .
(D) independent of both hardware and software.
Ans: D

Q.4 What is a relationship called when it is maintained between two entities?
(A) Unary
(B) Binary
(C) Ternary
(D) Quaternary
Ans: B

Q.5 Which of the following operation is used if we are interested in only certain columns of a table?
(A) PROJECTION
(B) SELECTION
(C) UNION
(D) JOIN
Ans: A

Q.6 Which of the following is a valid SQL type?
(A) CHARACTER
(B) NUMERIC
(C) FLOAT
(D) All of the above
Ans: D

Q.7 The RDBMS terminology for a row is
(A) tuple.
(B) relation.
(C) attribute.
(D) degree.
Ans: A

Q.8 Which of the following operations need the participating relations to be union compatible?
(A) UNION
(B) INTERSECTION
(C) DIFFERENCE
(D) All of the above
Ans: D

Q.9 The full form of DDL is
(A Dynamic Data Language
(B) Detailed Data Language
(C) Data Definition Language
(D) Data Derivation Language
Ans: C

Q.10 Which of the following is an advantage of view?
(A) Data security
(B) Derived columns
(C) Hiding of complex queries
(D) All of the above
Ans: D

Q.11 Which of the following is a legal expression in SQL?
(A) SELECT NULL FROM EMPLOYEE;
(B) SELECT NAME FROM EMPLOYEE;
(C) SELECT NAME FROM EMPLOYEE WHERE SALARY = NULL;
(D) None of the above
Ans: B

Q.12 The users who use easy-to-use menu are called
(A) Sophisticated end users.
(B) Naïve users.
(C) Stand-alone users.
(D) Casual end users.
Ans: B

Q.13 Which database level is closest to the users?
(A) External
(B) Internal
(C) Physical
(D) Conceptual
Ans: A

Q.14 Which are the two ways in which entities can participate in a relationship?
(A) Passive and active
(B) Total and partial
(C) Simple and Complex
(D) All of the above
Ans: B

Q.15 The result of the UNION operation between R1 and R2 is a relation that includes
(A) all the tuples of R1
(B) all the tuples of R2
(C) all the tuples of R1 and R2
(D) all the tuples of R1 and R2 which have common columns
Ans: D

Q.16 Which of the following is a comparison operator in SQL?
(A) =
(B) LIKE
(C) BETWEEN
(D) All of the above
Ans: D

Q.17 A set of possible data values is called
(A) attribute.
(B) degree.
(C) tuple.
(D) domain.
Ans: D

Q.18 Which of the operations constitute a basic set of operations for manipulating relational data?
(A) Predicate calculus
(B) Relational calculus
(C) Relational algebra
(D) None of the above
Ans:C

Q.19 Which of the following is another name for weak entity?
(A) Child
(B) Owner
(C) Dominant
(D) All of the above
Ans: A

Q.20 Which of the following database object does not physically exist?
(A) base table
(B) index
(C) view
(D) none of the above
Ans: C

Q.21 NULL is
(A) the same as 0 for integer
(B) the same as blank for character
(C) the same as 0 for integer and blank for character
(D) not a value
Ans: D

Q.22 Which of the following is record based logical model?
(A) Network Model
(B) Object oriented model
(C) E-R Model
(D) None of these
Ans: A

Q.23 A data dictionary is a special file that contains:
(A) The name of all fields in all files.
(B) The width of all fields in all files.
(C) The data type of all fields in all files.
(D) All of the above.
Ans: D

Q.24 A file manipulation command that extracts some of the records from a file is called
(A) SELECT
(B) PROJECT
(C) JOIN
(D) PRODUCT
Ans: A