Database Management System (DBMS) MCQ Questions and answers

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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) dependent non-key attributes are put in a separate table

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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) when there is dependent attributes in two possible composite keys one of the attributes is unnecessarily duplicated in the tuples

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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) i and iii

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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) Professor(professor, project) Professor( professor, project, dept) Student (student no, st_name, dept)

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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) by putting dependent non-key attribute in a separate table

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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) The general-purpose remarks column problem

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Q. Using the SQL GROUP BY phrase with a SELECT statement can help detect which of the following problems?

(A) The multivalue, multicolumn problem
(B) The inconsistent values problem
(C) The missing values problem
(D) None of the above is correct.

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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) neither of these two conditions is met.

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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) is impossible to do, so a new database must be constructed and the data moved into it.

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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) GROUP BY

Database Management System (DBMS) MCQs with answers Page - 155

Q. A relation is said to be in BCNF when

Q. A 3 NF relation is converted to BCNF by

Q. BCNF is needed because

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

Q. A 3 NF relation is split into 4 NF

Q. Using the SQL GROUP BY phrase with a SELECT statement can help detect which of the following problems?

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?

Q. The NOT EXISTS keyword will be true if:

Q. Changing cardinalities in a database is:

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