It seems to me that ID_JOB in Job Log table corresponds to ID_BATCH in other logging tables. Is my understanding correct? Why the name is made different?

Is ID_JOB/ID_BATCH generated by selecting the max ID_JOB from the Job Log Table? If so, does it mean that if my job/transformation is not enabled with table logging, the job will have no Batch ID?

Is appropriate locking done for fetching the max ID_JOB? I want to make sure that the ID will be unique even I am running several jobs concurrently at the same time.