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.

Which of the following is an example of roll up operation?

The roll-up operation aggregates the data by ascending the location hierarchy from the level of the city to the level of the country. When a roll-up is performed by dimensions reduction, one or more dimensions are removed from the cube. For example, consider a sales data cube having two dimensions, location and time.

What is rollup in data warehouse?

Roll-up is performed by climbing up a concept hierarchy for the dimension location. … On rolling up, the data is aggregated by ascending the location hierarchy from the level of city to the level of country. The data is grouped into cities rather than countries.