C# cannot insert data into SQL Server database

Question

I'm recently new at C# and follow a tutorial on connection to the database, the connection for viewing or SELECT command was ok, I made some revision based on the threads of forums to make my code better, but when I was in INSERT for my SQL Server, I have some problems. I was able to insert the data but when I re-run the program the data that I just inserted earlier was not in the database.

Here is my code on insert

string commandText = "INSERT INTO loginInfo (name, pass, role) VALUES(@name, @pass, @role)";

using (connection = new SqlConnection(connectionString))
{
    SqlCommand command = new SqlCommand(commandText, connection);
    command.CommandType = CommandType.Text;

    command.Parameters.AddWithValue("@name", textBox1.Text);
    command.Parameters.AddWithValue("@pass", textBox2.Text);
    command.Parameters.AddWithValue("@role", textBox3.Text);

    try
    {
        command.Connection.Open();
        command.ExecuteNonQuery();
    }
    catch
    {
    }
    finally
    {
        command.Connection.Close();
    }
}

I'm trying to create a simple CRUD but not save the data... please help

remove the empty catch block and check the exception. it should tell you what's wrong — doerig
– doerig, Commented May 12, 2016 at 8:40
+1 to @doerig . Never keep empty catches. Please try step by step debugging and check where u are getting the exception. Execute nonquery return 'int' that will tell you the status of insert, whether data is inserted or not. — Sandeep Kushwah
– Sandeep Kushwah, Commented May 12, 2016 at 8:45
@yok2xDuran using will close the connection, you don't have to use that finally block. The entire try/catch block you used simply hides the error, nothing more — Panagiotis Kanavos
– Panagiotis Kanavos, Commented May 12, 2016 at 8:47
Can you show us the connection string you're using, please? I suspect you might be using the AttachDbFileName= clause in there which is known to cause trouble — marc_s
– marc_s, Commented May 12, 2016 at 8:51

marc_s · Accepted Answer · 2016-05-12 08:54:53Z

6

If you're using the AttachDbFileName= clause in your connection string, you might have fallen victim to a well-known issue : you might just be looking at the wrong database (file) when checking your data.

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 connection.Close() call - and then inspect the .mdf file with SQL Server Mgmt Studio Express - I'm almost certain your data is there.

The long-term viable solution in my opinion would be to:

install SQL Server Express (and you've already done that anyway)
install SQL Server Management Studio Express
create your database in SSMS Express, give it a logical name (e.g. YourDatabase)
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=YourDatabase;Integrated Security=True
```
and everything else is exactly the same as before...

Also see Aaron Bertrand's excellent blog post Bad habits to kick: using AttachDbFileName for more background info.

answered May 12, 2016 at 8:54

marc_s

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1 Comment

Deo Over a year ago

thanks it work, i installed SSMS Express and it worked, i thing the database that i use was a service-based database, i was able to add it by right clicking on the explorer and added the service-based database

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