问gorm for mysql:找不到记录

EN

 // for trade_service
 type AmountConfig struct {
    MaxCny float64 `thrift:"max_cny,1" json:"max_cny"`
    MaxBtc float64 `thrift:"max_btc,2" json:"max_btc"`
  }
  //

type AmountConfig struct {
     gorm.Model
     trade_service.AmountConfig  //
}



func getAmountConfig() (amount_config *trade_service.AmountConfig, err error) {
    db, err := getORMDB()
    if err != nil {
      logger.Errorln(err)
      return
    }

    var amountConfig AmountConfig{}

    if err = db.First(&amountConfig).Error; err != nil {
        logger.Errorln("getAmountConfig amount record does not exist:", err)
        return
    }

    amount_config = trade_service.NewAmountConfig()
    amount_config.MaxCny = amountConfig.MaxCny
    amount_config.MaxBtc = amountConfig.MaxBtc

    logger.Infoln("get amountConfig ok", amount_config)

    return
}

CREATE TABLE `amount_config` ( 
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `max_cny` decimal(65,2) DEFAULT NULL,
 `max_btc` decimal(65,4) DEFAULT NULL,
 `created_at` datetime DEFAULT NULL,
 `deleted_at` datetime DEFAULT NULL, 
 `updated_at` datetime DEFAULT NULL,
  PRIMARY KEY (`id`), 
  KEY `updated_at` (`updated_at`),  
  KEY `created_at` (`created_at`),
  KEY `deleted_at` (`deleted_at`) 
  ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;