· 11 min read
Who Owns This Fact? Assign Ownership Per Datum Before You Integrate, Not After
When several integrated systems each hold a version of the same fact and each can write it, there is no answer to which one is right. Not a hard answer, no answer: there is no shared clock, no shared sequence, and last-write-wins gives you determinism rather than truth. Fact ownership has to be assigned per datum before integration. This covers the single-writer rule, read-only projections with provenance, what actually happens when two systems both update, and why sync is not an answer.