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

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

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

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();

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

And here is my connection String 

<?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>
marc_s
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panindra
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  • @marc_s i have updated question and added connection string ..where im going wrong – panindra Jul 18 '12 at 19:12
  • Any error message? Have you tried to debug the app step by step to see what's going on? Debugger is your best friend, learn to use it. Code you've shown looks ok, I'd bet there's a problem somewhere else (like you forgot to wire up even handlers and similar stuff). – walther Jul 18 '12 at 19:13
  • @walthereven i am getting no error . i tried iwth try catch it is ok – panindra Jul 18 '12 at 19:20

1 Answers1

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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!

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.

The real solution in my opinion would be to

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

  2. install SQL Server Management Studio Express

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

  4. 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

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

marc_s
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  • thansk for your suggestion .i will try form scratch once again – panindra Jul 18 '12 at 20:05
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    I agree with this analysis. I hate attaching mdfs in SSE, it can cause a lot of weird issues. I would create the SSE DB in SSMS, just like you would in full blown Sql Server, and use the connection string for that format, not using .mdf at all. That should give you fewer headaches. – GrayFox374 Jul 18 '12 at 20:30