962 views

Given an instance of the STUDENTS relation as shown as below

 StudentID StudentName StudentEmail StudentAge CPI $2345$ Shankar [email protected] X $9.4$ $1287$ Swati [email protected] $19$ $9.5$ $7853$ Shankar [email protected] $19$ $9.4$ $9876$ Swati [email protected] $18$ $9.3$ $8765$ Ganesh [email protected] $19$ $8.7$

For $(StudentName, StudentAge)$ to be a key for this instance, the value $X$ should NOT be equal to______.

edited | 962 views
0
why not 18?
+1

value X should NOT be equal to 19 is correct answer.

if u say why not 18 ? then i ask u why not 17 ?

Should not eqaul to $19$.

Since if it is equal the same key will have two different values for "StudentEmail" which cannot be true by the definition of candidate/primary/super key.
edited
There is already an entry with same name and age as 19. So the age of this entry must be something other than 19.
+1 vote
X Is NOt Equal 19

Because Primary Key  unique Key It Uniquely Identify All Tuples If It is  19  It has Same Value As Another Tuple So  Other Then 18 Id Preferble

1
2