-- Walk-forward 每个窗口（train 定参 → test 冻结，plan.md §25）
-- 由 src/hdiv/data/schema.py 生成，请勿手工修改
CREATE TABLE IF NOT EXISTS `hd_walkforward_window` (
  `id`              BIGINT       NOT NULL AUTO_INCREMENT,
  `wf_id`           VARCHAR(32)  NOT NULL,
  `window_index`    INT          NOT NULL,
  `train_start`     DATE         NOT NULL,
  `train_end`       DATE         NOT NULL,
  `test_start`      DATE         NOT NULL,
  `test_end`        DATE         NOT NULL,
  `frozen_params_json` TEXT      NOT NULL COMMENT '由 train 段确定、在 test 段冻结的参数',
  `train_run_id`    VARCHAR(32)  NULL,
  `test_run_id`     VARCHAR(32)  NULL,
  `created_at`      DATETIME     NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uq_hd_wf_win` (`wf_id`,`window_index`),
  KEY `ix_hd_wf_win_period` (`test_start`,`test_end`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci COMMENT='Walk-forward 窗口';