Top 1000+ Solved DataBase Management System (DBMS) MCQ Questions Answer
Q. To remove a relation from an SQL database, we use the command.
a. delete
b. purge
c. remove
d. drop table
Q. Updates that violate are disallowed.
a. integrity constraints
b. transaction control
c. authorization
d. ddl constraints
Q. The subset of a super key is a candidate key under what condition?
a. no proper subset is a super key
b. all subsets are super keys
c. subset is a super key
d. each subset is a super key
Q. Which one of the following attribute can be taken as a primary key?
a. name
b. street
c. id
d. department
Q. Which one of the following cannot be taken as a primary key?
a. id
b. register number
c. dept_id
d. street
Q. The clause is used to list the attributes desired in the result of a query.
a. where
b. select
c. from
d. distinct
Q. Which of the following statements contains an error?
a. select * from emp where empid = 10003;
b. select empid from emp where empid = 10006;
c. select empid from emp;
d. select empid where empid = 1009 and lastname = ‘geller’;
Q. In SQL the spaces at the end of the string are removed by function.
a. upper
b. string
c. trim
d. lower
Q. If we want to retain all duplicates, we must write in place of union.
a. union all
b. union some
c. intersect all
d. intersect some
Q. The number of attributes in relation is called as its
a. cardinality
b. degree
c. tuples
d. entity
Q. The is essentially used to search for patterns in target string.
a. like predicate
b. null predicate
c. in predicate
d. out predicate
Q. A indicates an absent value that may exist but be unknown or that may not exist at all.
a. empty tuple
b. new value
c. null value
d. old value
Q. The predicate in a where clause can involve Boolean operations such as and. The result of true and unknown is false and unknown is while unknown and unknown is
a. unknown, unknown, false
b. true, false, unknown
c. true, unknown, unknown
d. unknown, false, unknown