ALTER TABLE "FlowBoardDraft"
  DROP CONSTRAINT IF EXISTS "FlowBoardDraft_userId_unique";

ALTER TABLE "FlowBoardDraft"
  ADD COLUMN IF NOT EXISTS "title" varchar(256) DEFAULT '未命名流程白板' NOT NULL;

UPDATE "FlowBoardDraft"
SET "title" = '流程白板'
WHERE "title" = '未命名流程白板';

CREATE INDEX IF NOT EXISTS "FlowBoardDraft_user_title_idx"
  ON "FlowBoardDraft"("userId", "title");