/// <summary>
        /// AddTeacherPosition(TeacherPosition teacherPosition):添加一个教师职位记录
        /// </summary>
        /// <param name="teacherPosition"></param>
        /// <returns></returns>
        public bool AddTeacherPosition(TeacherPosition teacherPosition)
        {
            string sql = "insert into TeacherPosition(TeacherPositionName, TeacherPositionDescription) values(@TeacherPositionName, @TeacherPositionDescription)";

            SqlParameter[] parameters =
            {
                new SqlParameter("@TeacherPositionName",        SqlDbType.VarChar, 50),
                new SqlParameter("@TeacherPositionDescription", SqlDbType.VarChar, 200)
            };
            parameters[0].Value = teacherPosition.TeacherPositionName;
            parameters[1].Value = teacherPosition.TeacherPositionDescription;
            int n = DBHelper.ExecuteCommand(sql, parameters);

            return(n == 1);
        }
        /// <summary>
        /// GetAllTeacherPosition():获取所有的教师职位
        /// </summary>
        /// <returns></returns>
        public IList <TeacherPosition> GetAllTeacherPosition()
        {
            IList <TeacherPosition> listTeacherPosition = new List <TeacherPosition>();
            string sql = "select * from TeacherPosition";

            using (SqlDataReader reader = DBHelper.ExecuteReader(sql))
            {
                while (reader.Read())
                {
                    TeacherPosition teacherPosition = new TeacherPosition();
                    teacherPosition.TeacherPositionId          = int.Parse(reader["TeacherPositionId"].ToString());
                    teacherPosition.TeacherPositionName        = reader["TeacherPositionName"].ToString();
                    teacherPosition.TeacherPositionDescription = reader["TeacherPositionDescription"].ToString();
                    listTeacherPosition.Add(teacherPosition);
                }
            }
            return(listTeacherPosition);
        }