Saama Technologies – SQL & RDBMS

Question 1 :

The relational scheme Scholar Management(name, courseNo, rollNo, grade) has the following functional dependencies :

name, courseNo -> grade

rollNo, courseNo -> grade

name ->rollNo

rollNo -> name

The highest normal form of this relational scheme is

Options : 

a. 1NF

b. 2NF

c. 3NF

d. BCNF

Answers : 

c. 3NF

 

Question 2 :

An irreversible error in a database system can be caused by :

Options : 

a. A transaction writes a data item after it is read by an uncommitted transaction

b. A transaction writes a data item after it is written by an uncommitted transaction 

c. All of the above

d. None of the above

Answers : 

b. A transaction writes a data item after it is written by an uncommitted transaction 

 

Question 3 :

The table itemMaster(item,cost) holds the item name and the respective cost of the item .If there all the items are having different cost, then what does the SQL query do :

Select item 

fromitemMaster as  B

where (select count(*)

fromitemMaster as T

whereT.cost>B.cost)<5

Options : 

a. Displays the 5th most costly item

b. Displays the 5th most cheapest item

c. Displays the 4 most costly items

d. Displays the 5 most costly items

Answers : 

d. Displays the 5 most costly items

 

Question 4 :

State TRUE or FALSE

Every relation in BCNF is also in 3NF

Options : 

a. TRUE

b. FALSE

Answers : 

a. TRUE

 

Question 5 :

State TRUE or FALSE

Every relation in 3NF is also in BCNF

Options : 

a. TRUE

b. FALSE

Answers : 

b. FALSE

 

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