You use the alerters to track the changes in selected data and to configure the display of changed data. Use the formula language to build your custom alerters for formatting data changes. You can include special calculations based on data changes. For example, you can include a calculation to show the difference between the previous value and the current value of a measure.
When you track data changes, you select a particular data refresh as a reference point. This data is known as the reference data. When you activate the data tracking, you see your data in relation to the reference data.
Formatting to track changes either automatically or manually. You can track the following types of data change:
In automatic data tracking mode, you always compare the current data with the data before the last refresh. This is achieved by automatically setting the current data as the reference data just before each refresh. The reference data is always one refresh behind the current data. Automatic data tracking is appropriate for scheduled documents when you want to compare the current data with the data before the last refresh.
In manual data tracking mode, you select the reference data. You continue to use this data as a reference point until you update the reference point.