Data not saving permanently to SQL table

Question

I am using C# for a WPF application in Visual Studio Express 2012. I followed the tutorial found here. I created a testDb.mdf local Service-based database. I

Answer 1

Well, i found the solution. I solved it by installing SSDT(SQL server data tools) for visual studio. Install it according to your visual studio version. Go to following link to download the SSDT for visual studio. https://msdn.microsoft.com/en-us/mt186501

Answer 2

It is a common scenario. You have a connection string that uses the substitution string |DataDirectory|. In a desktop application this directory is usually the same directory where your program runs. Inside Visual Studio, your program runs in the BIN\DEBUG (or x86 variant) directory. Thus the Visual Studio copies your MDF file from the project directory to the BIN\DEBUG folder. You add records to this copy, not to the one in the project folder. However, the Visual Studio Server Explorer window has a connection that points to the Project Folder database that, of course, remains empty.

You could add another connection to the Server Explorer pointing to the folder BIN\DEBUG and check that your database has been updated or not.

To complicate the matter, there is the property Copy to the Output Directory associated with the MDF file. If this property is set to Copy Always everytime you start a new session within Visual Studio, the file is copied again from the project folder to the output directory (BIN\DEBUG) overwriting the copy already there with a new empty one. So the first run succeds, the second one fails.
The symptoms that you observed are a clear sign of this situation.

Simply change the property Copy to the Output directory to Copy if newer, the code works well.
(Peraphs it is too early, but remember to change your query to a parameterized query. As is, you could break your code simply inserting a single quote in the txtName textbox like O'Malley, not to mention the Sql Injection hack)

Answer 3

I think your issue is not with the insert code. It's with the way you're checking the database/table yourself. Particularly because you say you're getting primary key errors so something's being added to the table.

Are you sure you're refreshing your view of the table properly? Are you sure you're checking the right table in the right database?

Answer 4

In the following of the Steve's answer you can get your database full path in properties window and substitute it with |DataDirectory| in string connection.

your code will be like

conn.ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=G:\MhD\c#\phonebook\phonebook\phonebook\tellbook.mdf;Integrated Security=True";

Answer 5

Make sure your initial catalog is set in your connection string, and be sure you are pointing to the right server/ instance of SQL. You may have multiple instances of SQL Server on the same server or whatever DB Server you are using. Also ensure you're going to the right table, of course.

using (SqlConnection cn = new SqlConnection(@"Persist Security Info=False;Integrated Security=true;Initial Catalog=testDB;server=(local)"))
{           
            string sql = "INSERT INTO Test (TestInsert) Values('" + txtName.Text + "')";
            SqlCommand cmd = new SqlCommand(sql, cn);
            cn.Open();
            cmd.ExecuteNonQuery();
            MessageBox.Show("Added new record", "Message", MessageBoxButton.OK);

}

Check in SQL Server Studio that the database exists. I don't recommend using the filename mdf in your code directly using AttachDbFilename. Use the initial catalog.