- Applies
- when someone asks to exchange a shift
- Enforcement
- Hard: never broken
- Who sets it
- Fixed in the product
- Family
- Data integrity
- Roster style
- published baseline (shift exchange)
verifiedCompiled from the product source on 12 September 2026
Rule catalogue · Data integrity
A swap cannot change a shift already in the past
Breaking it rewrites a shift that has already been worked, so the roster stops matching what actually happened.
What data integrity rules protect
Not every rule is about people. This family holds the structural invariants: an assignment cannot exist in two places at once, history cannot be rewritten, a swap has to be aligned on both sides. They are mostly fixed in code rather than configurable, because they are not policy choices. They are the difference between a roster and a spreadsheet that looks like one.
Other rules in this family
- Externally owned assignments cannot be reassigned
- Assignments already worked cannot be reassigned
- A locked assignment stays with the person it names
- A replacement assignment stays with its replacement
- A swapped shift stays with the person who took it
- Externally owned pattern blocks cannot be reassigned
- Pattern blocks already worked cannot be reassigned
- A locked pattern block stays with the person it names