Top 1000+ Solved DataBase Management System (DBMS) MCQ Questions Answer
Q. Given the following relation Student (roll no, name, course no, course max. marks, year of study, address)The corresponding 3 NF relations are
a. student (roll no, name, year of study, address) course (course no, course max. marks)
b. student ( roll no, name, year of study, address) student (roll no, course no) course (course no, course max. marks)
c. student (roll no , name, address) year (roll no, year of study) course (course no, course max. marks)
d. student (roll no, name, address) course (course no, course max. marks, year of study)
Q. BoyeCodd Normal Form (BCNF) is needed when
a. two non-key attributes are dependent
b. there is more then one possible composite key
c. there are two or more possible composite overlapping keys and one attributeof a composite key is dependent on an attribute of another composite key
d. there are two possible keys and they are dependent on one another
Q. A relation is said to be in BCNF when
a. it has overlapping composite keys
b. it has no composite keys
c. it has no multivalued dependencies
d. it has no overlapping composite keys which have related attributes
Q. A 3 NF relation is converted to BCNF by
a. removing composite keys
b. removing multivalued dependencies
c. dependent attributes of overlapping composite keys are put in a separateRelation
d. dependent non-key attributes are put in a separate table
Q. BCNF is needed because
a. otherwise tuples may be duplicated
b. when a data is deleted tuples may be lost
c. updating is otherwise difficult
d. when there is dependent attributes in two possible composite keys one of the attributes is unnecessarily duplicated in the tuples
Q. Given the relation Supplier(s_id, p_order, s_name, qty) Given that there is a unique s_name for each s_id and that s_id, p_order is a composite key, find the correct statement among the following: i. this relation is a BCNF ii. this is 3 NF relation iii. this is a 2 NF relation iv. this is a 1 NF relation
a. i and ii
b. ii and iii
c. i and iv
d. i and iii
Q. A relation project guidance Project Guidance(professor, project, student no. st-name, dept) A professor can give many projects to many students A project will have many students A project may be guided by many professors The 4 NF relation corresponding to this are
a. Prof_Project (professor, st_name, dept) Proj_stud (project, student no.)
b. Prof_stud (professor, student no) Proj_stud (project, student no)
c. Student (student no, st_name, dept) Student (student no, st_name, dept)
d. Professor(professor, project) Professor( professor, project, dept) Student (student no, st_name, dept)
Q. A 3 NF relation is split into 4 NF
a. by removing overlapping composite keys
b. by splitting into relations which do not have more than one independent multi valued dependency
c. removing multivalued dependency
d. by putting dependent non-key attribute in a separate table
Q. Using the SQL GROUP BY phrase with a SELECT statement can help detect which ofthe following problems?
a. The multivalue, multicolumn problem
b. The inconsistent values problem
c. The missing values problem
d. The general-purpose remarks column problem
Q. What SQL command will allow you to change the table STUDENT to add the constraint named GradeCheck that states that the values of the Grade column must be greater than 0?
a. ALTER TABLE STUDENT ALTER CONSTRAINT GradeCheck (Grade > 0);
b. ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck (Grade > 0);
c. ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0);
d. None of the above is correct.
Q. The NOT EXISTS keyword will be true if:
a. any row in the subquery meets the condition.
b. all rows in the subquery fail the condition.
c. both of these two conditions are met.
d. neither of these two conditions is met.
Q. Changing cardinalities in a database is:
a. a common database design task.
b. a rare database design task, but does occur.
c. a database design task that never occurs.
d. is impossible to do, so a new database must be constructed and the data moved into it.
Q. The SQL keyword(s) ________ is used with wildcards.
a. LIKE only
b. IN only
c. NOT IN only
d. IN and NOT IN
Q. If a relationship has a cascade updates constraint, then if ________ in the parent table is changed, then the same change will automatically be made to any corresponding foreign key value.
a. the primary key
b. any alternate key
c. a surrogate key
d. a foreign key