Question

我正在尝试在从数据库中读取数据时更新数据，请参阅下文。但是在整个过程结束后，数据没有得到更新。

我需要指定任何交易语法吗？（当我调试时，我可以看到我找到了正确的记录。）

using (conn = new SqlConnection(MyConnectionString))
                using (SqlCommand cmd = new SqlCommand("dbo.MyProcedure", conn))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@Count", count);
                    conn.Open();
                    using (SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection))
                    {
                        while (reader.Read())
                        {
                            // wrapper object, not related to database
                            SampleModel c = new SampleModel();  
                            c.ID= (string)reader["ID"];
                            c.Name = (string)reader["Name"];
                            c.Type = (int)reader["Type"];

                            // modeList will return to outside, not related to database
                            modelList.Add(c);

                            sampleTable1  table1 = context.sampleTable1s.SingleOrDefault(t=> t.id = c.ID);   

                            // try to update the "isRead", but it doesn`t work....!!!
                            // about the datatype, in the data base, it is "smallInt"
                            // in linq to sql, it is "short?"
                            // PS Default value all should be 0
                            table1.isRead = 1;
                            context.SubmitChanges();  <--- here, it doesn`t do the job // context is new from Linq to SQL
                        }
                    }
                    conn.Close();
                }

这是我的程序：

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE PROCEDURE MyProcedure    
    @Count int = 100
AS
BEGIN

  SELECT TOP (@Count )
         t1.id AS ID, 
         t1.name AS Name, 
         t2.type AS TYPE    
    FROM sampleTable1 as t1 with (nolock), 
         sampleTable2 as t2 with (nolock)          
   WHERE (t1.t2Id = t2.Id)     
ORDER BY t1.name asc

END
GO

如果我将所有代码放在TransactionScope块

中

using (TransactionScope scope = new TransactionScope())
{
    // all the C# code above
    scope.Complete();
}

我将收到异常“服务器上的MSDTC'localhost-sqlserver2005'不可用。”

如果我只放了一些代码，没有例外，但数据没有更新

using (TransactionScope scope = new TransactionScope())
{
    sampleTable1  table1 = context.sampleTable1s.SingleOrDefault(t=> t.id = c.ID);   

    table1.isRead = 1;
    context.SubmitChanges(); 

    scope.Complete();
}

感谢。

Answer 1

检查所讨论的实体类中至少有一个成员在L2S设计器中被标记为主键成员。如果一个实体没有任何PK成员，L2S会在提交更新时默默地忽略它（无异常抛出，因为没有抛出异常，也没有生成更新的SQL语句并发送给db）。

Answer 2

确保您为该表设置了主键。如果您不能在db中执行此操作，请在linq2sql设计器中执行此操作。

已回复此here，here和here。还提到了linq to sql pitfalls。

为什么我不能使用LINQ to SQL将数据更新到数据库中？

2 个答案: