Software Architecture

Question 1

 

Consider a relation R= (A, B, C, D, E, F, G) satisfies following functional dependencies

{A→B, BC→DE, AEF→G}

What will be the closure of {A, C}+ ?

Select one:

a. {A, B, C}

b. {C,D,E,F,G}

c. {A,B,E,F,G}

d. {A,B,C,D,E}.

The correct answer is: {A,B,C,D,E}

Question 2

 

which the relation R with four attributes A, B, C and D the functional dependencies

{(A, B)→ (C, D) and C→D}

Which of the following statement is/are correct?

Select one:

a. Functional dependency C →D violates 3NF 

b. C is Key for relation R

c. R is in 3NF

d. R is in BCNF.

The correct answer is: Functional dependency C →D violates 3NF

Question 3

 

There are two relations X and Y. Relation X has arity 1 cardinality 2, relation Y has arity 3 and cardinality 4. Indicate the result of the SQL statement SELECT COUNT (*) FROM X, Y.

Select one:

a. 6

b. 8 

c. 4

d. cannot be calculated from given information.

The correct answer is: 8

Question 4

 

Display all the information for everyone in the employee who is a clerk

Select one:

a. Select * from employee where title = '_';

b. Select * from employee where title =”clerk';

c. Select * from employee;

d. None of them.

The correct answer is: Select * from employee where title =”clerk';

Question 5

 

which of the following is used to add new attribute (column) in the existing relation schema?

Select one:

a. INSERT

b. CREATE

c. DROP

d. ADD.

The correct answer is: ADD

Question 6

 

A given relation is known to be in third normal form. Select the statement which can be inferred from this

Select one:

a. Every determinant is a candidate key

b. Each non-key attribute is determine by the primary key 

c. Each non-key attributes determine the primary key

d. All attributes contributes to the primary key.

The correct answer is: Each non-key attribute is determine by the primary key

Question 7

 

Relation R has attributes A, B, C, D, E, F, G, H, I, J and satisfies FD's

ABD → E, C → J, AB→G, CI→I, B→F, G→HI

Find the candidate key

Select one:

a. A,B,C,D,G

b. A,B,C,I

c. A,B,C,D,E

d. A,B,C,D.

The correct answer is: A,B,C,D

Question 8

Incorrect

Mark 0.00 out of 1.00

 

Consider a banking database with the following table with three attributes loans (br_name, loan_no, amount). Find the appropriate query for the given statements below "Find the loan number for each loan of an amount greater than 20000"

Select one:

a. {t|∀ S ∈ loans (t[loan_no] =S[loan_no] ∧ [amount] > 20000}

b. None of them 

c. {t|t ∈ loans ∧ t [amount] >20000} where't' is a tuple

d. {t|∃ S ∈ loans (t[loan_no] =S[loan_no] ∧ [amount] > 20000}.

The correct answer is: {t|∃ S ∈ loans (t[loan_no] =S[loan_no] ∧ [amount] > 20000}

Question 9

 

Which of the following statement is false?

Select one:

a. A decomposition of relation, into BCNF is not unique.

b. The decomposition approach using the BCNF may produce inter_relational join constraints.

c. Any relation can be decomposed into a number of relations that are in 3NF, such decomposition is lossless and preserver the dependencies

d. Any relation can be decomposed losslessly into relations in BCNF and decomposition into BCNF always preserve dependency.

The correct answer is: Any relation can be decomposed losslessly into relations in BCNF and decomposition into BCNF always preserve dependency

Question 10

 

All operation that will increase the length of a list is

Select one:

a. Modify

b. All of them

c. Insert 

d. lookup.

The correct answer is: Insert

Question 11

 

DDL and DML statement are compiled and executed by

Select one:

a. Data model

b. Storage manager

c. Transaction manager

d. Query processor.

The correct answer is: Query processor

Question 12

 

 The SQL expression

Select Distinct T.branch_name from branch T, branch S where T.assets > S.assets and S>branch_city = "PONDICHERRY"  find the names of 

Select one:

a. the branch that have greater asset in pondicherry 

b. All branch that have greater assets then any branch located in pondicheery  c. all branch that have greater assets that all branch located in pondicherry 

d. any branch that have greater asset that any branch located in pondicerry.

The correct answer is: All branch that have greater assets then any branch located in pondicheery 

Question 13

 

which of the following is generally a benefit of normalization?

Select one:

a. Performance is improved

b. Number of tables is reduced

c. Selection anomalies are avoided

d. Insertion anomalies are avoided.

The correct answer is: Insertion anomalies are avoided

Question 14

 

In SQL, which command is used to remove rows from a table

Select one:

a. Both truncate and delete 

b. Delete

c. Truncate

d. Remove.

The correct answer is: Both truncate and delete

Question 15

 

Select the relational expression which could possibly return the following result

 

A

C

1

2

2

3

Select one:

a. σa<c(Πa,c R) 

b. Πa,c (σa=c R)

c. Πa<2R

d. Πa<c(Πa,c R).

The correct answer is: σa<c(Πa,c R)

Question 16

 

which of the following is updatable?

Select one:

a. View with a single defining table if view attributes contain the primary key or some other candidate key of the base relation 

b. All of the them

c. View defined using grouping and aggregate functions

d. View defined on multiple tables using joins.

The correct answer is: View with a single defining table if view attributes contain the primary key or some other candidate key of the base relation

Question 17

 

Lack of normalization can lead to which one of the following problems?

Select one:

a. Deferred Updates 

b. Insertion Problems  

c. Deadlock

d. Lost up dates.

The correct answer is: Insertion Problems 

Question 18

 

Consider a selection of the form SA<= 100(r), where r is a relation with 1000 tuples. Assume that the attribute values for A among the tuples are uniformly distributed in the interval [0,500]. Which one of the following options is the best estimate of the no of tuples returned by the given selection query?

Select one:

a. 100

b. 50

c. 200 

d. 150.

The correct answer is: 200

Question 19

 

Which of the following is correct?

Select one:

a. An SQL query automatically eliminates duplicates

b. None of them 

c. An SQL query will not work if there are no indexes on the relations.

d. SQL permits attributes names to be repeated in the same relation.

The correct answer is: None of them

Question 20

 

Information about a collection of student is given by the relation stud info (studid, name, sex). The relation enroll (studid, courseid) gives which student has enrolled for (or taken) what course(s). Assume that every course is taken by at least one male and at least one female student. What does the following relational algebra expression represent?

ΠCourseid ((Πstudid (σsex = 'female' (studinfo)) × Πcourseid (enroll))-enroll)

Select one:

a.

Course in which a proper subset of female students are enrolled  

b.

Course in which only male students are enrolled 

c.

Course in which all the female students are enrolled

d.

None of them.

The correct answer is:

Course in which a proper subset of female students are enrolled 

Question 21

Incorrect

Mark 0.00 out of 1.00

 

a lack of normalization can lead to which one of the following problem?

Select one:

a. Insertion problem 

b. Deferred Updates

c. Deadlock

d. Lost updates.

The correct answer is: Deferred Updates

Question 22

 

Which of the following is a low-level operator?

Select one:

a. Insert

b. Delete

c. Directory 

d. Update.

The correct answer is: Directory

Question 23

 

which of the following is not a low high level operator?

Select one:

a. Project

b. Update 

c. Select

d. Join.

The correct answer is: Update

Question 24

 

Null values in SQL indicate ____

1. Zero value

2. Value is unknown

3. Value does not exist

Select one:

a. 1 and 2

b. Only 3

c. All of these

d. 2 and 3.

The correct answer is: 2 and 3

Question 25

 

which of the following is correct statement about SQL?

Select one:

a. Data control language provides facilities to retrieve data

b. Data definition language provides facilities to add more data into a database while providing integrity of data

c. Data definition language provides facilities to modify structures of tables 

d. Data manipulation language can delete all records and tables in database.

The correct answer is: Data definition language provides facilities to modify structures of tables