National Champion Test - GATE 2018 CS : Database for GATE & PSU CS Exams

Question 1

Consider a relational schema R = {A, B, C, D, E, F, G} and the following functional dependencies hold: {AB ⇒ C, BC⇒ D, E⇒A, D⇒E, F⇒G}.
Which of the following are candidate keys of R?

Question 2

A relation R(A, B) where A, B are attributes is always in:

Question 3

R is relationship with 1 : 1 cardinality, 30% participation at E₁ end, 70% participation at E₂ end. Which is the best possible design?

Question 4

When number of entities are bought together into one entity based on their similar characteristics, what is this process called

Question 5

How many minimum tables (RDBMS Tables) required for the following ER Diagram which satisfy 2NF?

Question 6

In a B+ tree, if the search key value is 8 bytes long, the block size is 512 bytes and the block pointer size is 2 bytes, then maximum order of the B+ tree is _____.

Question 7

Consider a join (relation algebra) between relations r(R)and s(S) using the nested loop method. There are 3 buffers each of size equal to disk block size, out of which one buffer is reserved for intermediate results. Assuming size (r(R)) < size (s(S)), the join will have fewer number of disk block accesses if

Question 8

Consider the relation R(A, B, C, D) which of the following relational algebra expression returns the lowest value of A.(R₁ and R₂ are just renames of R)

Question 9

Relation R (A, B) has the following view defined on it:
CREATE VIEW V AS
(SELECT R1.A, R2.B
FROM R AS R1, R AS R2
WHERE R1.B=R2.A)
(i) The current contents of relation R are shown below. What are the contents of the view V?

The tuples (2, 11) and (11, 6) are now inserted into R. What are the additional tuples that are inserted in V?

Question 10

Consider a database that has the relation schema CR (StudentName, CourseName). An instance of the schema CR is as given below.

The following query is made on the database.

The number of rows in T2 is _____.

Question 11

Consider the following relations
Customer (c_id, name, city)
Branch (b_id, manager, city)
Account (acc_id, b_id, c_id, balance)
bid is foreign key of Account referencing Branch, c_id is the foreign key of Account referencing Customer.
Which of the following SQL queries find the managers of the Branch with total asset over 10000.

Question 12

Which of the following operators is used to search a specified pattern in a column?

Question 13

Which command undo all the updates performed by the SQL in the transaction?

Question 14

Suppose a database schedule S involves transactions

Construct the precedence graph of S with vertices representing the transactions and edges representing the conflicts. If S is serializable, which one of the following orderings of the vertices of the precedence graph is guaranteed to yield a serial schedule?