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ROLL-UP:The roll-up operation also called drill-up or aggregation operation performs aggregation on a data cube, either by climbing up a concept hierarchy for a dimension or by climbing down a concept hierarchy i.e dimension reduction.
It goes from less-detailed data to more-detailed data.
CUBE:OLAP cube is a method of storing data in a multidimensional form, generally for reporting purposes.
In addition to the regular aggregation results we expect from the GROUP BY clause, the ROLLUP extension produces group subtotals from right to left and a grand total.
Lets say you have table with two columns a,b.
a = 1,2
b = 3,4
Regular aggregation is will return 4 rows (2x2)
1,3
1,4
2,3
2,4
Rollup will return SUBTOTALS for every row from the right plus one subtotal for all rows (like sum on no aggregation) .
There would be 7 rows :
1,3
1,4
1,null
2,3
2,4
2,null
null,null
CUBE
In addition to the subtotals generated by the ROLLUP extension, the CUBE extension will generate subtotals for all combinations of the dimensions specified. If "n" is the number of columns listed in the CUBE, there will be 2n subtotal combinations.
Lets say you have table with two columns a,b.
a = 1,2
b = 3,4
Cube will return SUBTOTALS for every row in every direction plus one subtotal for all rows (like sum on no aggregation) .
There would be 9 rows :
OLAP Operation Types
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Can anyone explain how the cube and rollup work?
ROLL-UP:The roll-up operation also called drill-up or aggregation operation performs aggregation on a data cube, either by climbing up a concept hierarchy for a dimension or by climbing down a concept hierarchy i.e dimension reduction. It goes from less-detailed data to more-detailed data.
CUBE:OLAP cube is a method of storing data in a multidimensional form, generally for reporting purposes.
ROLLUP
In addition to the regular aggregation results we expect from the GROUP BY clause, the ROLLUP extension produces group subtotals from right to left and a grand total. Lets say you have table with two columns a,b.
a = 1,2
b = 3,4
Regular aggregation is will return 4 rows (2x2)
1,3
1,4
2,3
2,4
Rollup will return SUBTOTALS for every row from the right plus one subtotal for all rows (like sum on no aggregation) . There would be 7 rows :
1,3
1,4
1,null
2,3
2,4
2,null
null,null
CUBE
In addition to the subtotals generated by the ROLLUP extension, the CUBE extension will generate subtotals for all combinations of the dimensions specified. If "n" is the number of columns listed in the CUBE, there will be 2n subtotal combinations.
Lets say you have table with two columns a,b.
a = 1,2
b = 3,4
Cube will return SUBTOTALS for every row in every direction plus one subtotal for all rows (like sum on no aggregation) . There would be 9 rows :
1,3
1,4
1,null
2,3
2,4
2,null
null,3
null,4
null,null
Thanks Aldo.
Can you please relate this to the actual problem and help me to understand how it comes to the solution D (4,7,3,84,160,117).
Appreciate your time..
No problem, sorry for the late reply. The tuple must satisfy the equation :
a,b,c,
/* Aggregation number of rows */ a*b*c,
/* Cube number of rows */ a*b*c+a*b+b*c+a*c+a+b+c+1,
/* Rollup number of rows */ a*b*c+a+a*b+1
And only one answers satisfies this.
Hello Aldo,
This is really helpful to understand,However I have one question about Rollup tuples count:- Intstead of a*b*c+a+a*b+1,it should be ,a*b*c+a+b+c+1
I think it goes from smaller combination to bigger, like this:
/* Aggregation */ (a*b*c),
/* Cube */ 1+a+b+c+(a*b)+(b*c)+(c*a)+(a*b*c),
/* Rollup */ 1+a+(a*b)+(a*b*c)