EF数据库框架：使用DbTypeName创建特殊参数类型(Oracle/MySql数据库）

        /// <summary>
        /// 创建SQL参数
        /// </summary>
        /// <param name="name">参数名称</param>
        /// <param name="dbTypeName">参数类型名称（如：Varchar2, RefCursor）</param>
        /// <param name="direction">参数方向</param>
        /// <param name="value">参数值</param>
        /// <returns></returns>
        DbParameter CreateParameter(string name, object value, string dbTypeName, ParameterDirection direction);

            var p1 = db.CreateParameter("PARAM1", "code1");
            var p2 = db.CreateParameter("PARAM2", "code2");
            var p3 = db.CreateParameter("PARAM3", DateTime.Today);
            var p4 = db.CreateParameter("OUTPUT_CURSOR", null, "RefCursor", ParameterDirection.Output); //创建特殊类型参数

            var data = db.GetDataTable("USP_TEST", CommandType.StoredProcedure, p1, p2, p3, p4);

                    //输入参数
                    if (ParameterDirection.Input == ioType)
                    {
                        Type type = db.meta_ConvertToDotNetType(item.ParamType);//数据库类型转.NET类型
                        Object value = TypeDescriptor.GetConverter(type).ConvertFromString(item.ParamValue ?? "");
                        listParam.Add(db.CreateParameter(item.ParamName, value, item.ParamType, ioType));
                    }
                    else if (ParameterDirection.Output == ioType)
                    {
                        DbParameter p = db.CreateParameter(item.ParamName, item.ParamValue ?? "", item.ParamType, ioType);
                        p.Size = 10000000;
                        listParam.Add(p);
                    }