Click OK. In the Aggregation tab, select Based on dimensions. In the Aggregation tab, from the Formula list, select a rule. If you need to create more complex formulas, click the Expression Builder button

8-16 Metadata Repository Builders Guide for Oracle Business Intelligence Enterprise Edition data if it has a row for every combination of its associated dimension levels. When setting up aggregate rules for a measure column, you can specify that data is dense only if all the logical table sources to which it is mapped are dense. To specify a default aggregation rule for a measure column: 1. In the Business Model and Mapping layer, double-click a logical column. 2. In the Logical Column dialog, click the Aggregation tab. 3. In the Aggregation tab, choose one of the following options: ■ For measures in which the additivity is the same in all dimensions in other words, for fully-additive or non-additive measures, select one of the aggregate functions from the Default Aggregation Rule list. The function you select is always applied when a user or an application requests the column in a query, unless an override aggregation expression has been specified. When you select Count Distinct as the default aggregation rule, you can specify an override aggregation expression for specific logical table sources. Choose this option when you have more than one logical table source mapped to a logical column and you want to apply a different aggregation rule to each source. Click the Add button to select logical table sources for which you want to specify individual aggregation rules. In the Browse dialog, select the logical table source you want to add, and click OK. Then, in the Formula list for that logical table source, select the aggregation rule you want to use. ■ Select Based on dimensions if your measure has different additivity for different dimensions in other words, for semi-additive measures. For example, select this option for inventory units that sum in all dimensions except time. See Setting Up Dimension-Specific Aggregate Rules for Logical Columns for more information about this feature. Click the Add button to select additional dimensions for which you want to specify aggregation rules. In the Browse dialog, select the dimension you want to add, and then click OK. Then, in the Formula list for that dimension, select the aggregation rule you want to use, or click the Expression Builder button to build the aggregation rule using Expression Builder. The Data is dense option appears when you select Based on dimensions. Select this option only if all the logical table sources to which this column is mapped are dense.

4. Click OK.

Setting Up Dimension-Specific Aggregate Rules for Logical Columns The majority of measures have the same aggregation rule for each dimension. However, some measures can have different aggregation rules for different dimensions. For example, bank balances might be averaged over time but summed Caution: Selecting Data is dense indicates that all sources to which this column is mapped have a row for every combination of dimension levels that they represent. Selecting this option when any table source that is used by this column does not contain dense data will return incorrect results. Working with Logical Tables, Joins, and Columns 8-17 over the individual accounts. The Oracle BI Server lets you configure dimension-specific aggregation rules. You can specify one aggregation rule for a given dimension and specify other rules to apply to other dimensions. You need to configure dimensions in the Business Model and Mapping layer to set up dimension-specific aggregation. For more information about setting up aggregate navigation, see Chapter 10 . To specify dimension-specific aggregation rules for a single logical column: 1. In the Business Model and Mapping layer, double-click a logical column. 2. In the Logical Column dialog, click the Aggregation tab.

3. In the Aggregation tab, select Based on dimensions.

4. In the Browse dialog, select a dimension over which you want to aggregate, and then click OK.

5. In the Aggregation tab, from the Formula list, select a rule.

After selecting rules for specified dimensions, set the aggregation rule for any remaining dimensions by using the dimension labeled Other.

6. If you need to create more complex formulas, click the Expression Builder button

to the right of the Formula column to open Expression Builder. 7. If you have multiple dimensions, you can click Up or Down to change the order in which the dimension-specific rules are performed. When calculating the measure, aggregation rules are applied in the order top to bottom established in the dialog.

8. Click OK.