Comparison
Canonical datasetvsSingle source of truth
Canonical dataset
there is one table everyone agrees is the answer for orders, and the other four are explicitly labelled as derived or deprecated.
One agreed authoritative dataset for a given concept, with everything else derived from it. It is easy to say and organisationally difficult, because the competing copies usually exist for good local reasons and removing one costs somebody their workflow. The achievable version is not one table but one lineage root plus a clear statement of which derivations are sanctioned.
Full entry →Single source of truth
the same value was stored in two places and they drifted apart, so the header and the sidebar disagreed.
The rule that each piece of state is owned in exactly one place and everything else reads it from there. Every duplicate is a synchronisation bug waiting for the update path that forgets one copy. The most common violation is copying a prop into state on mount, which quietly stops tracking the prop from then on.
Full entry →