[1] Tuple is a ………………….. in a relation
a) row b) column
c) attribute d) none of these
Ans: (a) row
[2] Primary Key can be NULL.
a) Yes b) Sometimes
c) No d) None of these
Ans: (c) No
[3] Referential Integrity means
a) relationship with Foreign Key and Primary Key
b) relationship with Candidate Key and Primary Key
c) relationship with Candidate Key and Foreign Key
d) none of these
Ans: (a) relationship with Foreign Key and Primary Key
[4] The project operation displays
a) rows of a relation b) keys of a relation
c) columns of a relation d) none of these
Ans: (c) columns of a relation
[5] A relation is a
a) combination of rows and columns b) combination of primary keys
c) combination of join operations d) none of these
Ans: (a) combination of rows and columns
[6] The mapping cardinality for a binary relationship between entity sets A and B can be
a) one to one only
b) one to many only
c) many to one only
d) one to one, one to many, many to one, many to many.
Ans: (d) one to one, one to many, many to one, many to many.
[7] The collection of information stored in a database at a particular moment is
a) view b) instance
c) scheme d) none of these
Ans: (b) instance
[8] Which operator in SQL performs pattern matching?
(A) BETWEEN operator (B) LIKE operator
(C) EXISTS operator (D) None of these
Ans: (B) LIKE operator
[9] Which of the following is an aggregate function in SQL?
a) Select b) SUM
c) Ordered by d) None of these
Ans: (b) SUM
[10] Record based data models are used to
a) specify overall logical structure of the database
b) describe data and its relationships
c) higher-level description of storage structure and access mechanism
d) all of these
Ans: (d) all of these
[11] Consider the join of a relation R with a relation S. If R has m tuples and S has n tuples, then the maximum and minimum size of the join respectively are
a) m + n and 0 b) m + n and [m – n]
c) mn and 0 d) mn and m + n
Ans: (c) mn and 0
[12] An attribute of one table matching the primary key of another table, is called
a) foreign key b) secondary key
c) candidate key d) composite key
Ans: (a) foreign key
[13] Data dictionary contains
a) names of relations b) names of indexes
c) names of attributes d) all of these
Ans: (d) all of these