you need a formula field in related records of service to figure out if the record is active, which could be:
"status" : if( Get(CurrentDate)≥ start date AND Get(CurrentDate)≤ end date; 1 ; 0)
(calculation field result needs to be set as number)
on the Master record you set a calculation field (result as needed, but text if you take the example below:
if ( sum ( related_table::status) < 1; "inactive"; "active")
hope that helps
In contract, you can define this unstored calculation field:
If ( IsEmpty ( FilterValues ( List ( Services::Status ) ; "Active" ) ) ; "Inactive" ; "active" )
In my related file I have a field for the status that I can toggle off or on. As a service is added to Active and when a service is cancelled it is marked in active. When all services have been cancelled, then I wanted the Master record to show Inactive.
Thank you both for the quick responses. Thank you Phil for the solution I was drawing a blank on.