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Aggregation rules identify the aggregation operators for each dimension of the cube, the order of aggregation, and the hierarchies included in the aggregation. All measures in a compressed cube must use the cube aggregation rules. For uncompressed cubes, you can specify unique aggregation rules for each measure
These options appear only when defining measure aggregation rules:
Measure: Select a measure from the list to define its aggregation rules.
Use aggregation specification from the cube: The aggregation rules for the selected measure default to the rules for the cube.
Choose an aggregation operator for each dimension and specify the order:
Order: The order in which the dimensions are aggregated. When the aggregation operators are the same across all dimensions, the order is not important. However, some combinations of operations produce different results depending on the order in which they are calculated. To change the order, select a dimension and use the arrow keys to move it up or down the list.
Dimension: The dimensions in the measure that will be aggregated.
Operator: Choose the type of calculation you wish to perform across each dimension. See Table: OLAP Aggregation Operators.
Based On: When using a weighted or scaled operator, select a measure that contains weight factors. The measure must be dimensioned by the dimension being aggregated, and can optionally be dimensioned by other dimensions in the cube.
Aggregate From Level: The level at which aggregation starts. This is typically the lowest level in the hierarchy. However, it can be a higher level if multiple hierarchies share the lower levels or if the lower levels are preaggregated before loading into the cube.
Aggregate the cube/measure using selected hierarchies: Select one or more hierarchies for each dimension being aggregated. If you omit a hierarchy, then no aggregate values are stored for it; they are always calculated in response to a query. Because this will degrade runtime performance, you should omit a hierarchy only if it is seldom used.
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