OLAP Basics

OLAP  Reporting

OLAP Cube Modeling

Aggregate Weights

Aggregate weights are used when a Member must be assigned a multiplied value in an aggregation in order for the data to be properly represented. For example, in the Accounts hierarchy, Cost of Sales should be handled as a negative number in the Gross Profit aggregation because it will represent an amount subtracted from Gross Profit (i.e., Gross Profit = Net Sales – Cost of Sales). To designate Cost of Sales as a negative number in the Gross Profit aggregation, we can assign it a weight of “–1”. This means that the data included in Cost of Sales will always be multiplied by –1 when it is rolled up in the Hierarchy.

1. Return to the Accounts Hierarchy dialog box (double-click on Accounts in the Dimensions dialog), and double-click: Cost of Sales in the Hierarchy Definition box on the right.

Note that, to the right of Cost of Sales, a box appears where “1” is highlighted and where you can enter a weight for the Member.

2. Enter -1 in the box so that it appears as follows:

3. Click the “OK” button, , to return to the Dimension dialog box.
4. Click “OK” again to be returned to the Main Application Window

In PowerOLAP, the default Aggregate weight is equal to “1”. Thus, a parent Aggregate member is simply the sum of all Child Members defined in the Dimension Hierarchy. In the example exercise, all Aggregates you defined are standard with the exception of gross profit, in the Accounts dimension. Therefore, you do not need to define Aggregate weights for the remaining Aggregate members.

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