When creating a Project variable, you can define it as a Business Indicator variable. This allows the variable to be stored in BAM the database.
When you add Business Indicator variable to your process, a column is added to the following BAM database tables: Workload, Task Performance and Process Performance. The name of this column is the Business Indicator name preceded by the prefix "V_".
If you define a business dimension, the workload table contains one row for each possible value of this business dimension present in the process. Each row shows the quantity of instances that match that business dimension. If the business dimension has a numeric type, the value stored in BAM tables indicates the range that corresponds to the value of the business dimension.
When you define a measurement business variable, the sum of this variable's value for all in flight instances is stored into workload table. If business dimensions were defined as well, then this sum will be divided into as many rows as business dimension values present in flight instances.
Task performance table stores one row for each instance that completes an activity. Each of these rows contains the value of dimensions and measurements at the time the instance completed the activity.
In a similar way, process performance table stores one row for each instance that gets to the end activity. Each of these rows contains the value of dimensions and measurements at the time the instance completed the whole process.