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Using Datasets with Decision Support Components
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The only decision support component that binds directly to a dataset is the decision cube, TDecisionCube. TDecisionCube expects to receive data with groups and summaries defined by an SQL statement of an acceptable format. The GROUP BY phrase must contain the same non-summarized fields (and in the same order) as the SELECT phrase, and summary fields must be identified.

The decision query component, TDecisionQuery, is a specialized form of TQuery. You can use TDecisionQuery to more simply define the setup of dimensions (rows and columns) and summary values used to supply data to decision cubes (TDecisionCube). The decision query has no properties than are not inherited from other components. Important inherited properties are Active and SQL.

You can also use a TQuery or TTable component as a dataset for TDecisionCube, but the correct setup of the dataset and TDecisionCube are then the responsibility of the designer.

To work correctly with the decision cube, all projected fields in the dataset must either be dimensions or summaries. The summaries should be additive values (like sum or count), and should represent totals for each combination of dimension values. For maximum ease of setup, sums should be named "Sum..." in the dataset while counts should be named "Count...".

The Decision Cube can pivot, subtotal, and drill-in correctly only for summaries whose cells are additive. (SUM and COUNT are additive, while AVERAGE, MAX, and MIN are not.) Build pivoting crosstab displays only for grids that contain only additive aggregators. If you are using non-additive aggregators, use a static decision grid that does not pivot, drill, or subtotal.

Since averages can be calculated using SUM divided by COUNT, a pivoting average is added automatically when SUM and COUNT dimensions for a field are included in the dataset. Use this type of average in preference to an average calculated using an AVERAGE statement.

Averages can also be calculated using COUNT(*). To use COUNT(*) to calculate averages, include a "COUNT(*) COUNTALL" selector in the query. If you use COUNT(*) to calculate averages, the single aggregator can be used for all fields. Use COUNT(*) only in cases where none of the fields being summarized include blank values, or where a COUNT aggregator is not available for every field.

See Also

Using Decision Cubes

Using Decision Sources

Using Decision Pivots

Creating and Using Decision Grids

Creating and Using Decision Graphs

Working with Queries

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