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Thursday, September 8, 2016

How many tuples will be resulted in a cartesian product operation

How many records will the cartesian product operation produce?


Question:


5. Assume relations R and S with tuples 10 and 5 respectively. How many records will be there in the result of the operation R X S (i.e., R cartesian product S)?

(a) 10 records
(b) 5 records
(c) 50 records
(d) 15 records



Answer:

(c) 50

R X S will include every tuple of R with every tuple of S and produce a redundant number of records. Refer the example given below;



R

A
B
C
Tuple 1
a1
b1
c1
Tuple 2
a2
b2
c2
Tuple 3
a3
b3
c3

S

B
D
Tuple 1
b1
d1
Tuple 2
b2
d3

R X S

A
R.B
C
S.B
D
Tuple 1
a1
b1
c1
b1
d1
Tuple 2
a1
b1
c1
b2
d3
Tuple 3
a2
b2
c2
b1
d1
Tuple 4
a2
b2
c2
b2
d3
Tuple 5
a3
b3
c3
b1
d1
Tuple 6
a3
b3
c3
b2
d3










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