The data definition is an optional component used to configure default properties for a given piece of data in one place. Using this component eliminates or reduces the additional configuration required on analytic proxy extensions and widget (Chart, Table, Label) bindings.

Consider a data definition for hs:power. In this example, you only need to configure Aggregation and Rollup.

Figure 33.   Data definition for aggregation

In the screen capture, Aggregation is configured as Sum and Rollup is configured as Avg. Other properties, such as the Missing Data Strategy, Outlier and Raw Data Filter are useful but only applicable to analytic requests with trend data.

Figure 34.   Result of the Sum function

Once the framework processes the analytic request (the interval poller on the analytic proxy extension triggers every five seconds) the Out slot updates and displays the sum of the four MainKw point values (2352.8).

Notice that the Aggregation property of Sum on the data definition has overridden the default Aggregation function of First.

Now, instead of using a data definition to configure Aggregation, you can explicitly configure the Aggregation property on the Proxy Ext.

Figure 35.   Aggregation property configured on the Proxy Ext

In the screen capture, Aggregation is set to Max, which should override the data definition Aggregation property. The result in the Out slot is now 865.5.