schema_version: 1
decision:
  id: postgres-as-source-of-truth
  title: PostgreSQL as the single source of truth
  status: accepted
  date: 2026-09-02
  elements: [db, api, worker]
  diagrams: [0200-containers/online-shop.archify]
context: >
  Orders, customers and the catalogue were spread over the
  shop database and two spreadsheets kept by support.
  Refunds were reconciled by hand every Monday.
decision: >
  One PostgreSQL database owns orders, customers and the
  catalogue. The API is the only writer. Everything else
  (cache, search, reports) is derived and may be rebuilt.
consequences: >
  Support loses the spreadsheets and gets the admin console.
  Any new store must be declared derived or get its own
  decision. Backups and migrations are the API team's job.