{"id":"cdc-determines-insert-vs-update-by-old-value","text":"The CDC layer distinguishes `insert` from `update` events by checking whether `old_value is None`; the WAL only knows `PUT` and `DELETE`, so the semantic enrichment happens at the CDC boundary","truth_value":"IN","source":"entries/2026/05/29/topic-ddia-unbundling-concept.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"cdc-determines-insert-vs-update-by-old-value","truth_value":"IN","reason":"premise"}]}}