How do I count Entitys and display the Sum?

[julius-low-kernel]

Hey there,
my Workspace has Zones_DM, which have Person_DM-Entitys (n:m) as Bindings.
I would like to save the Sum of Person-Entitys in the Zone_DM, to display the current capacity.

In the Screenshot below, I would need the “Belegt”-field to be “2”, since there are 2 Person-Entitys bound to this specific zone.

[malcolm-silver-ice]

Hi @julius-low-kernel

You need a CDM to achieve this. You can take a look at the “advanced” Workspace to get some ideas on how to achieve this. I specifically recommend looking at PersonWithTeamsAndContracts_CDM which sums up the amount of time spent in different teams.

Remember to check the Data Services Migration instructions

• CDM based calculations only happen when the CDD is created (i.e. in the Frontend)
• You cannot sort based on Field Valuess if the Field only exists in the CDM (as is the case of SumOfAssignedTimeShare)
• You could sort based on Field Values if the value is written into a Field on the Document Model but this value may not be up-to-date if the CDD hasn’t been re-computed (see 1st point).

However you could express this as a Query which counts the number of linked documents.