本篇接C# SQL封装（三）
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）
/// <summary>
/// 更新一条数据的T-SQL构成（以id号来删除）
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="model">原始model</param>
/// <param name="model_change">更改后的model</param>
/// <returns></returns>
public static string UPDATE_T_SQL<T>(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）
/// <summary>
/// 构建T-SQL参数 UPDATE
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="model">原model</param>
/// <param name="model_change">更改后model</param>
/// <returns></returns>
public static SqlParameter[] UPDATE_T_SQL<T>(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<SqlParameter> 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<SqlParameter>();
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<SqlParameter>();
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<SqlParameter>();
}
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<User>(kayer_ori, kayer_change_copy);
SqlParameter[] update_p = SqlParameter_Structure.UPDATE_T_SQL<User>(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 ..........................
本文出自 “Better_Power_Wisdom” 博客，请务必保留此出处http://aonaufly.blog.51cto.com/3554853/1945666
原文：http://aonaufly.blog.51cto.com/3554853/1945666