Case ID
A case ID is the specific ID of a case that connects the individual steps of a process instance from the beginning to the end, for example, a customer number, order number, or patient ID.
For example, in an invoice approval process, a invoice number can be the case ID. One of the three minimum data requirements is to make your event log viable for process mining.
Every event in your process event log must refer to one specific case, so that process mining software can compare several executions of the process to one another.