Unit affiliation span

The Lifecycle

Transitions Explained

These names describe a dated span and term coverage, with withdrawn representing a removed row. Transfer creates a successor and merge chooses dated transfers or re-pointings. End accepts an explicit last day and can remove a row retrospectively when that day precedes its start.

What Cannot Happen

A connection with a successor cannot be withdrawn because lineage still references it. End can shorten an existing span; it cannot extend or reopen it. A separate record is used for later coverage.

Concurrency and Timing

Membership locking and affiliation version checks order changes. Unit sharing protects target validation against a simultaneous merge.