Consider a relational database containing the following schemas.
The primary key of each table is indicated by underlying the constituent fields.
SELECT s.sno, s.sname
FROM Suppliers s, Catalogue c
WHERE s.sno = c.sno AND
Cost > (SELECT AVG (cost)
FROM Catalogue
WHERE pno = ‘P4’
GROUP BY pno);
The number of rows returned by the above SQL query is
A
4
B
5
C
2
D
0
2
GATE CSE 2020
MCQ (Single Correct Answer)
+1
-0.33
Which one of the following is used to represent the supporting many-one relationships of a weak entity set in an entity-relationship diagram?
A
Rectangles with double/bold border
B
Diamonds with double/bold border
C
Ovals that contain underlined identifiers
D
Ovals with double/bold border
3
GATE CSE 2020
MCQ (Single Correct Answer)
+2
-0.67
Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE?
A
A cell in R holds a set instead of an atomic value.
B
R has a nontrivial functional dependency X $$ \to $$ A, where X is not a superkey and A is a non-prime attribute and X is not a proper subset of any key
C
R has a nontrivial functional dependency X $$ \to $$ A, where X is not a superkey and A is a non-prime attribute and X is a proper subset of some key.
D
R has a nontrivial functional dependency X $$ \to $$ A, where X is not a superkey and A is a prime attribute.
4
GATE CSE 2020
MCQ (Single Correct Answer)
+2
-0.67
Consider a schedule of transactions T1 and T2 :
Here, RX stands for “Read(X)” and WX stands for “Write(X)”. Which one of the following schedules is conflict equivalent to the above schedule?
