数据库文件不会更新

Question

I have created a Windows Forms application that is supposed to add a new record into a database. Now, it adds it successfully and the new data can be used... but when I close the application and start it again, the application acts as if nothing has changed.

The database was created in SQL Server and the application uses the .mdf file it generated.

Here is the method:

private void btnUnos_Click(object sender, EventArgs e)
{
            //create an instance of the row to be inserted
            PIScarinaDataSet.OsobaRow novaOsoba;
            novaOsoba = pIScarinaDataSet.Osoba.NewOsobaRow();

            //fill the attributes
            novaOsoba.Ime = txtImeOsobe.Text;
            novaOsoba.Drzavnost = dobijDrzavu();
            novaOsoba.Predstavlja = dobijPredstavnika();

            //insert into the database
            this.Validate();
            this.pIScarinaDataSet.Osoba.Rows.Add(novaOsoba);
            this.osobaTableAdapter1.Update(this.pIScarinaDataSet.Osoba);
            this.osobaBindingSource1.EndEdit();
}

Answer 1

Since this is what helped you, I will make it an answer:

[S]ince you're using the .MDF created by SQL Server, you need to make sure the "Copy to Output Directory" property on the file is set to "Copy if newer" in Visual Studio. (Or, "Do not copy" if you're going to manually put it in the correct directory.) That is, if you're actually saving the data and this is the issue.

Answer 2

You didn't show us the crucial part - the connection string of your application - but I'm guessing that it will contain something like AttachDbFileName=yourdatabase.mdf somewhere in there.

The whole User Instance and AttachDbFileName= approach is flawed - at best! When running your app in Visual Studio, it will be copying around the .mdf file (from your App_Data directory to the output directory - typically .\\bin\\debug - where you app runs) 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 myConnection.Close() call - and then inspect the .mdf file 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 (eg MyDatabase )

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=MyDatabase;Integrated Security=True 

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