实体框架4.1不会向SQL Server Express数据库添加任何行 [英] Entity Framework 4.1 is not adding any rows to SQL Server Express database

问题描述

使用带有SQL Server Express .mdf 数据库的Entity Framework 4.1。

Working with Entity Framework 4.1 with a SQL Server Express .mdf database .

出于测试目的，我是试图在WPF应用程序中使用实体模型在SQL Server Express数据库上执行CRUD操作。

For test purpose I am trying to perform CRUD operations on SQL Server Express database using Entity Model in a WPF application .

我是这个概念的新手，我按照视频教程进行了编码，并根据

I am new to this concept, and I followed the video tutorial and done coding according that

我创建了一个非常简单的表的实体模型。我在cs文件中编写了简单的代码，使用以下代码执行向数据库添加一行的操作

I created Entity model of single very simple table. And I wrote simple code in cs file to perform adding one row to the database using following code

testEntities db = new testEntities();
TestTable tb = new TestTable();
tb.Name = txtName.Text;
tb.Email = txtMail.Text;
db.TestTables.AddObject(tb);
db.SaveChanges();

但是如果我返回数据库，则不会添加任何数据。请告诉我这里出了什么问题??

But if I go back check the database no data is added. Please tell me whats going wrong here ??

这是我的连接字符串

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <connectionStrings>
    <add name="testEntities" 
         connectionString="metadata=res://*/DBModel.csdl|res://*/DBModel.ssdl|res://*/DBModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=.\SQLEXPRESS;attachdbfilename=|DataDirectory|\test.mdf;integrated security=True;connect timeout=30;user instance=True;multipleactiveresultsets=True;App=EntityFramework&quot;" 
         providerName="System.Data.EntityClient" />
  </connectionStrings>
</configuration>

推荐答案

整个用户实例和AttachDbFileName = 方法有缺陷-充其量！ Visual Studio将围绕 .mdf 文件（从 DataDirectory 复制到正在运行的应用程序的输出目录）和最有可能，您的 INSERT 可以正常工作-但是您只是在查看错误的 .mdf 文件！

The whole User Instance and AttachDbFileName= approach is flawed - at best! Visual Studio will be copying around the .mdf file (from the DataDirectory to the output directory of your running app) and most likely, your INSERT works just fine - but you're just looking at the wrong .mdf file in the end!

如果您要坚持使用这种方法，请尝试在 .SaveChanges（）调用上设置一个断点-然后使用SQL Server Mgmt Studio Express检查正在运行的应用程序目录中的 .mdf 文件-我几乎可以确定您的数据在那里。

If you want to stick with this approach, then try putting a breakpoint on the .SaveChanges() call - and then inspect the .mdf file in the running app's directory with SQL Server Mgmt Studio Express - I'm almost certain your data is there.

我认为真正的解决方案是

1. 安装SQL Server Express（而且您已经完成了此操作）

1. install SQL Server Express (and you've already done that anyway)

安装SQL Server Management Studio Express

install SQL Server Management Studio Express

在 SSMS Express 中创建数据库，并为其指定一个逻辑名称（例如 TestDatabase ）

create your database in SSMS Express, give it a logical name (e.g. TestDatabase)

使用其逻辑数据库名称（在服务器上创建时赋予该名称）连接到它-并且不要弄乱物理数据库文件和用户实例。在这种情况下，您的连接字符串将类似于：

connect to it using its logical database name (given when you create it on the server) - and don't mess around with physical database files and user instances. In that case, your connection string would be something like:

Data Source=.\\SQLEXPRESS;Database=TestDatabase;Integrated Security=True

其他所有内容与以前完全相同。 ..

and everything else is exactly the same as before...

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