docs: public static int getBatchUpdateCount(int[] batchExecuteResult){
  		int result = 0;
  		for (int c: batchExecuteResult){
  			if (c >= 0){
  				// real count
  				result += c;
  			}else if (c == -2){
  				// unknown
  				return -2;
  			}else{
  				// error or others
  				// do nothing
  			}
  		}
  		return result;
  	}