Example 1: Explicit Dimension Sets

The following table lists an analytic model's data cubes and their attached dimensions.

Data Cubes Data Cube Formula (if any) Attached Dimensions

SALES

UNIT_SALES * UNIT_PRICE

  • PRODUCTS

  • REGIONS

  • MONTHS

UNIT_SALES

None (input cube)

  • PRODUCTS

  • REGIONS

  • MONTHS

UNIT_PRICE

None (input cube)

  • PRODUCTS

  • REGIONS

  • MONTHS

The company:

  • Sells the hamburgers product in both the Africa and Asia regions during all months of the year.

  • Sells the french fries product in the Africa region only during the summer months.

  • Never sells the french fries product in the Asia region.

If you do not create an explicit dimension set to calculate these data cubes, the analytic calculation engine calculates the sales for all products in all regions during all months, even if some of these combinations are not valid. In other words, the analytic calculation engine calculates the sales for french fries for all months in Asia, even though the company does not sell french fries in Asia. Additionally, the analytic calculation engine calculates the sales for french fries during all months in Africa, even though the company only sells french fries in Africa during the summer.

In total, without using an explicit dimension set, the analytic calculation engine performs 48 calculations for the SALES data cube:

 (2 PRODUCTS * 2 REGIONS * 12 MONTHS)

The analytic calculation engine generates the value of 0 for each invalid member combination, taking valuable time to do so. These invalid member values are:

  • Not saved to the main record.

  • Not displayed to end users in the application.

    End users view invalid member combinations as blank cells.

To prevent this unneeded calculation of data, you should create an explicit dimension set consisting of the PRODUCTS, REGIONS, and MONTHS dimensions. The analytic calculation engine uses this explicit dimension set, plus the UNIT_SALES and UNIT_PRICE input data cubes, to determine the explicit tuples. Using these tuples, the analytic calculation engine calculates only the necessary values.

Note:

The analytic calculation engine uses the input cubes that comprise the relevant data cube's formula to instantiate the explicit tuples that it uses to calculate the data cube.

In total, the analytic calculation engine performs 27 calculations for the SALES data cube:

(1 PRODUCT * 2 REGIONS * 12 MONTHS) + (1 PRODUCT * 1 REGIONS * 3 MONTHS)