Hey! There is a question about foreign key in the database. In the act_ru_task table both fields execution_id and proc_inst_id refer to the act_ru_execution.id. Can you please explain logic of this? 
Hi @Klara,
this is only the case if you have linear processes without parallel gateway or embedded subprocesses or attached boundary events.
In the latter case, new executions are spawned as explained here: Process Variables | docs.camunda.org
Now the process instance id and the execution id will get different values.
Hope this helps, Ingo
Thank you, Ingo! 