Linq to sql（三）：增删改（四）

运行效果如下图：

在这里，我们通过Single方法获取一条记录，也就是一个tbGuestBook实例，

更新了一些属性后保存也就完成了改这个操作。删除操作更简单，只需要从表中移除对象。

你是不是觉得好像不是在操作数据库，像在操作内存中的对象。

       由于写了日志，看看改和删操作会是怎么样的SQL？

UPDATE [dbo].[tbGuestBook]

SET [IsReplied] = @p4, [Reply] = @p5

WHERE ([ID] = @p0) AND ([UserName] = @p1) AND ([PostTime] = @p2) AND ([Message] = @p3) AND (NOT ([IsReplied] = 1)) AND ([Reply] IS NULL)

-- @p0: Input Guid (Size = 0; Prec = 0; Scale = 0) [00000000-0000-0000-0000-000000000000]

-- @p1: Input String (Size = 4; Prec = 0; Scale = 0) [ghgh]

-- @p2: Input DateTime (Size = 0; Prec = 0; Scale = 0) [2007-8-16 10:20:09]

-- @p3: Input String (Size = 3; Prec = 0; Scale = 0) [ghj]

-- @p4: Input Boolean (Size = 0; Prec = 0; Scale = 0) [True]

-- @p5: Input String (Size = 3; Prec = 0; Scale = 0) [qqq]

-- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.20706.1

 

DELETE FROM [dbo].[tbGuestBook] WHERE ([ID] = @p0) AND ([UserName] = @p1) AND ([PostTime] = @p2) AND ([Message] = @p3) AND (NOT ([IsReplied] = 1)) AND ([Reply] = @p4)

-- @p0: Input Guid (Size = 0; Prec = 0; Scale = 0) [158ec941-13ff-4093-bd8b-9fceae152171]

-- @p1: Input String (Size = 2; Prec = 0; Scale = 0) [44]

-- @p2: Input DateTime (Size = 0; Prec = 0; Scale = 0) [2007-8-16 9:56:19]

-- @p3: Input String (Size = 2; Prec = 0; Scale = 0) [44]

-- @p4: Input String (Size = 3; Prec = 0; Scale = 0) [222]

-- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.20706.1