/// <summary>
        /// 判断是否存在引用
        /// </summary>
        /// <param name="db">数据库上下文</param>
        /// <param name="field">字典表对象</param>
        /// <returns>是否存在引用(true:是,false:否)</returns>
        public bool ExistsReference(SysEntities db, SysField field)
        {
            bool bResult = false;

            if (db != null && field != null)
            {
                String sql    = String.Format("select Value o from SysEntities.{0} as o where o.{1}=@id", field.MyTables, field.MyColums);
                var    reader = db.CreateQuery <DbDataReader>(sql, new ObjectParameter("id", field.Id));
                bResult = reader.Count() > 0;
            }

            return(bResult);
        }