CREATE TABLE IF NOT EXISTS "FlowBoardDraft" (
  "id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
  "userId" uuid NOT NULL REFERENCES "User"("id") ON DELETE cascade,
  "snapshot" jsonb NOT NULL DEFAULT '{"children":[]}'::jsonb,
  "createdAt" timestamp NOT NULL DEFAULT now(),
  "updatedAt" timestamp NOT NULL DEFAULT now(),
  CONSTRAINT "FlowBoardDraft_userId_unique" UNIQUE("userId")
);

CREATE INDEX IF NOT EXISTS "FlowBoardDraft_user_updated_idx"
  ON "FlowBoardDraft"("userId", "updatedAt");