For an application report I tried to include the number of database instances in a graph via a calculated metric.
A calculated metric is to my knowledge the best way of doing this. The calculated metric gives the ability to slice and dice on several perspectives like number databases per System Owner or per Business Owner in a graph.

Upon now unfortunately no luck in getting this graph to work.
I tried the following:
- Set up the calculated metric (see screenshot)

- The DB MW Master Data set provides the numbers to a object called 'SL080 Database and Middleware'. This model was created by ourselves (so no standard object from Apptio like Servers)
- I also tried to directly link the DB MW Master Data set to Applications via a Model step. This includes a join between Application and the data set (see screenshot)

- Secondly I tried to read out the value from the object itself by using this formula for the calculated metric '=SL080 Databased and Middleware.DB Count'
- Include a graph in the report on Application which directly retrieves the value from the SL080 Database and Middleware model. This works only for all applications, when I filter on System Owner the number of databases remains the total number of databases.