notes: Any Period in the system may be queried as to it's history.
notes: And we can also query the Active Period record, to see when any
Period has become the Active Period.
notes: Here we can see each change in the Active Period, and which Period
was activated as the Active Period, when and by whom.
notes: We can also query any on-line Period.
notes: In this case, we can track all status changes for this Period from
when it was first created, it's description given, and each and every
subsequent OPEN and CLOSE.
notes: For a Period that is no longer on-line, but rolled out, we can also
see the last Actions and when the Period was archived.
notes: Here we can see when the Period was Fixed and then subsequently