Maintaining OLAP Groups and OLAP Summary Data Stores

Example: Adding a Frequency Count to an OLAP Summary Data Store

For an OLAP summary data store, you might need the summary data to contain the frequency of each record. That is, you want a numeric column whose value represents the frequency of the rows for each combination of class column values. To produce the appropriate summary data:

Add a column to the summary data store.
Assign the added column as a statistic column, using the SUM statistic.
In the Mapping process for the summary data store, map the column to a value of 1.

Note: The following explanations describe only the metadata and methods that specifically apply to this example. [cautionend]

Add a Column to OLAP Summary Data Store

This explanation adds a column to an OLAP Table. You add a column from the Columns tab in the object's properties window, which for this example is the OLAP Table Properties window.

Columns Tab

specifies the columns to be included in the summary data store. To add a column that does not exist in the input data, define the column's attributes (name, type, length, description, format, and informat), then click Add. The result of adding a column to store frequency count follows:

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Assign OLAP Summary Roles to the Column

On the Columns tab, click OLAP to open the OLAP Column Roles window from which you assign specific OLAP summary roles.

Assign the freq column as a statistic column, using the SUM statistic, as follows:

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Define Mapping Process in Process Editor Job

The freq column must be mapped to a value of 1 as shown in the following Mapping Process Properties window:

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You can do this easily by using the stored expression Frequency Count, which is available in the Expression Builder window. That is, from the Column Mapping tab on the Mapping Process Properties window, select the column, then click Derived Mapping, which opens the Expression Builder window. From the Expression Builder window, select the Expressions component OLAP, and then Frequency Count.

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When you click OK on the Expression Builder window, the value of 1 is assigned to the freq column, and you are returned to the Column Mapping tab in the Mapping Process Properties window.

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