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Ans given: 100

asked | 84 views

Lets take an example, Below are three instances of table with ratio of tuples equal to the original relation.

A B C
Y  Y  L
P  Q  M
C  D  N
X  Z  O

C D E
L  Z  A
M  Z  A
N  Z  A
L  Z  B
M  Z  B
O  Z  B

E F
A  Z
B  Z

If we join tem in any way the resulting table will have 6 tuples
We can thus conclude that P join Q join R will result in 300 tuples.

A B C D E F
Y  Y  L  Z  A  Z
Y  Y  L  Z  B  Z
P  Q  M  Z  A  Z
P  Q  M  Z  B  Z
C  D  N  Z  A  Z
X  Z  O  Z  B  Z

answered by Active (2.3k points)
selected
I thought, C in Q is foreign key pointng to C in P and similarly E in Q referring to E in R.

So, we should not consider foreign key even if there is common attribute between two relation unless it is mentioned explicitly. ??
@Vijay. Yes. We shouldn't consider unless explicitly stated because we have satisfied the conditions they have given.
But, if options are given, we need to consider that C is foreign key in Q   :P
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