Obtaining Database Statistics

Use the Statistics sheet of the JADE Report Configuration window to obtain statistics about class instances and collection dimensions.

To access the Statistics sheet

• Click on the Statistics tab of the JADE Report Configuration window.

The Statistics sheet is then displayed.

The statistics are derived from the types and collections that you have included in your reporting view.

To display class and collection statistics

1. Select the Statistics sheet of the JADE Report Configuration window. A subset of your application is then displayed.

   These statistics can be used when running a report as part of the query optimization.

2. Expand the Object folder to display the classes and collections against which you want to run statistics.

3. Select the classes and collections against which you want to run statistics.

   To select more than one entity, use the standard action; that is, hold down the Shift key and then click the first and last entities in a range or hold down the Ctrl key and then click the entities you require that are not in a consecutive range.

4. Click the Update button to update statistics on the selected classes and collections.

The statistics are then updated, as shown in the following image of a typical statistics display.

For the selected classes, the display shows the number of instances of that class in your database. In the example in the above image, there are eight instances of the Agent class.

For selected collections, the display shows the average size of the collection and the standard deviation for that calculated average. In the example in the above image, the allSalesItems collection for the Agent class has an average of 13 entries over the eight agents in that class and the standard deviation is 4.17.

The allSalesItems collection for the Company class has an average size of 106 and a standard deviation of zero (0), as there is only one instance of the Company class, which encompasses all 106 sale items.