-- Durable canonical metadata for 0pt dataset versions.
-- Bytes remain canonical ST0RE artifacts referenced by artifact_refs.

CREATE TABLE IF NOT EXISTS opt_dataset_versions (
  dataset_id       text NOT NULL REFERENCES opt_datasets(dataset_id) ON DELETE RESTRICT,
  version          integer NOT NULL CHECK (version > 0),
  tenant_id        text NOT NULL,
  project_id       text NOT NULL,
  artifact_refs    text[] NOT NULL CHECK (cardinality(artifact_refs) > 0),
  schema_version   text NOT NULL,
  record_count     bigint CHECK (record_count IS NULL OR record_count >= 0),
  description      text,
  created_at       timestamptz NOT NULL DEFAULT now(),
  created_by       text NOT NULL,
  correlation_id   text,
  idempotency_key  text,
  PRIMARY KEY (dataset_id, version)
);

CREATE UNIQUE INDEX IF NOT EXISTS opt_dataset_versions_idempotency_idx
  ON opt_dataset_versions (tenant_id, idempotency_key)
  WHERE idempotency_key IS NOT NULL;

CREATE INDEX IF NOT EXISTS opt_dataset_versions_tenant_dataset_idx
  ON opt_dataset_versions (tenant_id, dataset_id, version DESC);

COMMENT ON TABLE opt_dataset_versions IS
  'Immutable 0pt dataset-version metadata. Content bytes remain in ST0RE artifacts.';