本篇接C# SQL封装（三）

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在其功能上继续扩展 改操作 ， 让我们开始吧。。。。。

一 ： 构建T-SQL语句（在SQL_Structure.cs中添加一个方法 UPDATE_T_SQL， 用于构建update的T-SQL）

        /// 

        /// 更新一条数据的T-SQL构成（以id号来删除）
        /// 
        /// 
        /// 原始model
        /// 更改后的model
        /// 
        public static string UPDATE_T_SQL(T model , T model_change) where T : BaseModel
        {
            Type model_type = model.GetType();
            Type model_change_type = model_change.GetType();
            if (model_type.Name == model_change_type.Name)
            {
                string base_update = @"update [{0}] set {1} where {2} = @{3}";
                string[] arr = model_type.Name.Split(new char[] { '.' });
                string table_name = arr[arr.Length - 1];//获得表的名称
                PropertyInfo[] p_intos = model_type.GetProperties();
                PropertyInfo item = null;
                PropertyInfo item_change = null;
                string item_value = string.Empty;
                string item_change_value = string.Empty;
                StringBuilder update_set = null;
                for (int i = 0; i < p_intos.Length; i++)
                {
                    item = p_intos[i];
                    item_change = model_change_type.GetProperty(item.Name);
                    item_value = item.GetValue(model, null).ToString();
                    item_change_value = item_change.GetValue(model_change, null).ToString();
                    if (item.Name == "id")
                    {
                        //比较id值是否一致
                        if (item_value != item_change_value)
                        {
                            throw new Exception(
                                string.Format("model类 id : {0} 与model_change类id:{1} 不一致,请确保是同一条数据",
                                    item_value,
                                    item_change_value
                                )
                                );
                        }
                    }
                    else
                    {
                        if (item_value != item_change_value)
                        {
                            if (update_set == null) update_set = new StringBuilder();
                            update_set.Append(
                                string.Format( @" {0} = @{1}," , item.Name , item.Name )
                                );
                        }
                    }
                }
                if (update_set != null)
                {
                    return string.Format( base_update,
                        table_name,
                        update_set.ToString().Substring(0, update_set.ToString().Length - 1),
                        "id",
                        "id"
                        );
                }
                else
                {
                    return string.Empty;//不存在更新
                }
            }
            else
            {
                throw new Exception(
                    string.Format("model类 : {0} 与model_change类 :{1} 不匹配",
                        model_type.Name ,
                        model_change_type.Name
                        )
                    );
            }
        }

二 ： 构建SqlParameter参数 （在SqlParameter_Structure.as中添加方法UPDATE_T_SQL）

        /// 

        /// 构建T-SQL参数 UPDATE
        /// 
        /// 
        /// 原model
        /// 更改后model
        /// 
        public static SqlParameter[] UPDATE_T_SQL(T model, T model_change) where T : BaseModel
        {
            Type model_type = model.GetType();
            Type model_change_type = model_change.GetType();
            if (model_type.Name == model_change_type.Name)
            {
                PropertyInfo[] p_intos = model_type.GetProperties();
                PropertyInfo item = null;
                PropertyInfo item_change = null;
                string item_value = string.Empty;
                string item_change_value = string.Empty;
                List sql_param = null;
                SqlParameter cell = null;
                bool is_change_model = false;//是否有字段进行了更改
                for (int i = 0; i < p_intos.Length; i++)
                {
                    item = p_intos[i];
                    item_change = model_change_type.GetProperty(item.Name);
                    item_value = item.GetValue(model, null).ToString();
                    item_change_value = item_change.GetValue(model_change, null).ToString();
                    if (item.Name == "id")
                    {
                        if (item_value != item_change_value)
                        {
                            throw new Exception(
                                string.Format("model类 id : {0} 与model_change类id:{1} 不一致,请确保是同一条数据",
                                    item_value,
                                    item_change_value
                                )
                                );
                        }
                        else
                        {
                            if (sql_param == null) sql_param = new List();
                            cell = new SqlParameter(item.Name, SqlParameter_Structure.Get_SqlDbType_SqlType(item.PropertyType));
                            cell.Value = item.GetValue(model, null);
                            sql_param.Add(cell);
                        }
                    }
                    else
                    {
                        if (item_value != item_change_value)
                        {
                            if (!is_change_model) is_change_model = true;
                            if (sql_param == null) sql_param = new List();
                            cell = new SqlParameter(item_change.Name, SqlParameter_Structure.Get_SqlDbType_SqlType(item_change.PropertyType));
                            cell.Value = item_change.GetValue(model_change, null);//加入改变的值
                            sql_param.Add(cell);
                        }
                    }
                }
                if (is_change_model)
                {
                    return sql_param.ToArray();
                }
                else
                {
                    return null;//没有任何字段更改
                }
            }
            else
            {
                throw new Exception(
                    string.Format("model类 : {0} 与model_change类 :{1} 不匹配",
                        model_type.Name,
                        model_change_type.Name
                        )
                    );
            }
        }

测试：

测试代码

            //------------------------模拟一条重数据库得到的数据 begin ---------------------------------------
            User kayer_ori = new User();
            kayer_ori.id = 3;
            kayer_ori.name = "kayer";
            kayer_ori.sex = 1;
            kayer_ori.lv = 1;
            kayer_ori.username = "Kayer";
            kayer_ori.userpwd = "123";
            //------------------------模拟一条重数据库得到的数据 end -----------------------------------------
            //拷贝一条kayer_ori数据 （ 可以用原型模式 ， 这里我直接使用笨办法 ）
            User kayer_change_copy = new User();
            kayer_change_copy.id = kayer_ori.id;
            kayer_change_copy.name = kayer_ori.name;
            kayer_change_copy.sex = kayer_ori.sex;
            kayer_change_copy.lv = kayer_ori.lv;
            kayer_change_copy.username = kayer_ori.username;
            kayer_change_copy.userpwd = kayer_ori.userpwd;
            // --- 改变数据 ---
            kayer_change_copy.name = "Aonaufly";
            kayer_change_copy.lv = 4;
            string sql_update = SQL_Structure.UPDATE_T_SQL(kayer_ori, kayer_change_copy);
            SqlParameter[] update_p = SqlParameter_Structure.UPDATE_T_SQL(kayer_ori, kayer_change_copy);
            int i = SqlHelper.ExecteNonQuery(CommandType.Text, sql_update, update_p);
            if (i > 0)
            {
                Console.WriteLine("执行操作成功");
            }
            else
            {
                Console.WriteLine("执行操作失败");
            }

结果 :

在数据库中：

未完待续 ..........................

新闻标题：C#SQL封装（四）
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