I have simple form which reads `users name`,`email`,and `city`. I have created a database and a table with fields `id`,`name`,`email` and `city`. When I run the code I don't encounter any errors or exceptions,but unable to see the inserted data into table. Following is my code 

```
SqlConnection con = 
    new SqlConnection("Data Source=(LocalDB)\\MSSQLLocalDB;AttachDbFilename=F:\\Database1.mdf;Integrated Security=True");
con.Open();
SqlCommand cmd = 
    new SqlCommand("insert into tbl_insert  values ( " + Convert.ToInt32(txtId.Text) + "," + "'" + txtName.Text + "'" + "," + "'" + txtEmail.Text + "'" + "," + "'" + txtboxCity.Text + "'" + ")", con);
cmd.ExecuteNonQuery();
con.Close();

```

I have attached my database screenshots.
 Database design:

[![enter image description here](https://i.stack.imgur.com/Qqju8.jpg)](https://i.stack.imgur.com/Qqju8.jpg)

This is output I get after running my code.
Output with null value stored:

[![enter image description here](https://i.stack.imgur.com/Jt21j.jpg)](https://i.stack.imgur.com/Jt21j.jpg)