now ATTRIBUTE C in schema S is renamed as A
FROM NOW C=A for schema S
and every attribute of A have to be CROSS PRODUCTED with attribute of B in schema S that is
S(A,B)
A |
B |
---|
1 |
5 |
1 |
6 |
1 |
7 |
1 |
9 |
2 |
5 |
2 |
6 |
2 |
7 |
2 |
9 |
3 |
5 |
3 |
6 |
3 |
7 |
3 |
9 |
8 |
5 |
8 |
6 |
8 |
7 |
8 |
9 |
NOW we have to find its INTERSECTION with R
R INTERSCTION S(A,B)
A |
B |
---|
1 |
5 |
2 |
6 |
3 |
7 |
so this nothing but the natural join of R and S
∮ formula should be just R.B= S.B