BB MotherShip

Whether a fridge temperature reading is within its safe range is a generated stored column, evaluated by Postgres from the reading and the range. Application code cannot get it wrong and cannot be persuaded to write a different answer. For a food-safety audit trail the authority has to sit at the lowest layer that a human cannot reach past.

is_in_range  GENERATED ALWAYS AS (
  temperature_c >= min_safe_c AND temperature_c <= max_safe_c
) STORED

Stock entries are unique on location, date, shift window and type, so re-submitting the form updates rather than duplicates. Anything filled in by a person under time pressure will be submitted twice; the choice is whether that produces a duplicate row or nothing at all. Sell-through is then computed on read rather than stored, so it cannot disagree with the entries it comes from.

A null location id marks a record as chain-wide, so one master set of menu items, recipes and suppliers is visible at every location while each site can still hold its own. Reads take the union of the current location and the global scope. The pattern is old and worth naming, because the alternative — copying the master set per location — is correct on the day it is written and wrong every day after.

The revenue outlook is a weighted confidence score over shifts, checklist completions and calendar events — three tables already being written for other reasons, no new migration, no new storage. Before adding a data source, check whether the signal is already in the building.

The first suite deliberately targets the utilities with a history: timezone conversion behind past off-by-a-day and wrong-hour bugs, rank thresholds and progress caps, PIN hashing round-trips and malformed input. Not coverage for its own sake — the specific pure functions whose failures had already cost something. Integration tests against row-level security still need a test database, and that is written down as an open gap rather than quietly skipped.