Database Management System Set 56

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This set of DataBase Management System (DBMS) Multiple Choice Questions & Answers (MCQs) focuses on Database Management System Set 56

Q1 | A table that contains one or more repeating groups is in which normal form?

1NF

2NF

3NF

Unnormalized Form

Q2 | A relation is said to be in 3 NF if(i) it is in 2 NF (ii) non-key attributes are independent of one another (iii) key attribute is not dependent on part of a composite key (iv) has no multi-valued dependency

i and iii

i and iv

i and ii

ii and iv

Q3 | Given the following relation it is not 3 NF because Student (roll no, name, course no, course max. marks, year of study, address)

it is not in 2 NF

it does not have composite key

non-key attributes course no and course max. marks are functionally dependent

it has more than 3 non-key attributes

Q4 | Given the following relation Student (roll no, name, course no, course max. marks, year of study, address)The corresponding 3 NF relations are

student (roll no, name, year of study, address) course (course no, course max. marks)

student ( roll no, name, year of study, address) student (roll no, course no) course (course no, course max. marks)

student (roll no , name, address) year (roll no, year of study) course (course no, course max. marks)

student (roll no, name, address) course (course no, course max. marks, year of study)

Q5 | BoyeCodd Normal Form (BCNF) is needed when

two non-key attributes are dependent

there is more then one possible composite key

there are two or more possible composite overlapping keys and one attributeof a composite key is dependent on an attribute of another composite key

there are two possible keys and they are dependent on one another

Q6 | A relation is said to be in BCNF when

it has overlapping composite keys

it has no composite keys

it has no multivalued dependencies

it has no overlapping composite keys which have related attributes

Q7 | A 3 NF relation is converted to BCNF by

removing composite keys

removing multivalued dependencies

dependent attributes of overlapping composite keys are put in a separateRelation

dependent non-key attributes are put in a separate table

Q8 | BCNF is needed because

otherwise tuples may be duplicated

when a data is deleted tuples may be lost

updating is otherwise difficult

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

Q9 | 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

i and ii

ii and iii

i and iv

i and iii

Q10 | 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

Prof_Project (professor, st_name, dept) Proj_stud (project, student no.)

Prof_stud (professor, student no) Proj_stud (project, student no)

Student (student no, st_name, dept) Student (student no, st_name, dept)

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

Q11 | A 3 NF relation is split into 4 NF

by removing overlapping composite keys

by splitting into relations which do not have more than one independent multi valued dependency

removing multivalued dependency

by putting dependent non-key attribute in a separate table

Q12 | Using the SQL GROUP BY phrase with a SELECT statement can help detect which ofthe following problems?

The multivalue, multicolumn problem

The inconsistent values problem

The missing values problem

The general-purpose remarks column problem

Q13 | 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?

ALTER TABLE STUDENT ALTER CONSTRAINT GradeCheck (Grade > 0);

ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck (Grade > 0);

ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0);

None of the above is correct.

Q14 | The NOT EXISTS keyword will be true if:

any row in the subquery meets the condition.

all rows in the subquery fail the condition.

both of these two conditions are met.

neither of these two conditions is met.

Q15 | Changing cardinalities in a database is:

a common database design task.

a rare database design task, but does occur.

a database design task that never occurs.

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

Q16 | Which one of the following sorts rows in SQL?

SORT BY

ALIGN BY

ORDER BY

GROUP BY

Q17 | The SQL keyword(s) ________ is used with wildcards.

LIKE only

IN only

NOT IN only

IN and NOT IN

Q18 | 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.

the primary key

any alternate key

a surrogate key

a foreign key

Q19 | For every relationship, how many possible types of actions are there when enforcingminimum cardinalities?

Two

Three

Four

Six

Q20 | In creating a procedure, you may get a message if you have compile errors. Which of the following is true?

The line numbers reported match the line numbers you see in your text editor.

SQL*Plus will automatically show the errors to you.

To see the errors, enter SHOW ERRORS in SQL*Plus.

If there are no syntax errors, you will receive the message "NO ERRORS.

Q21 | Which of the following is not true about indexes?

Indexes are created to enforce uniqueness on columns.

Indexes are created to enable fast retrieval by column values.

Columns that are frequently used with equal conditions in WHERE clauses are good candidates for indexes.

Indexes are created with the ALTER TABLE command.

Q22 | In ……….. normal forms, any multivalued attributes have been removed.

First

Second

Third

Fourth

Q23 | A (n) …………….. is an attribute in a relation that serves as a primary key of another relation in the same.

Composite key

Foreign key

Identifier key

Primary key

Q24 | In the process of decomposition is called as

Normalization

Generalization

Aggregation

Specalization

Q25 | A relation Schema R is in ……….. if it is in 3NF and satisfies an additional constant thatfor every FD X->A. X must be a candidate key.

1 NF

2 NF

3 NF

BCNF

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