Question

This code doesn’t change the column (I try to increase the column orderTillNow value by one…), table: items.

SqlConnection connection = new SqlConnection("Data Source=***:*******.com;Initial Catalog=****;User ID=*****;Password=******;Integrated Security=False;");

using (SqlCommand command = new SqlCommand("UPDATE items SET ordersTillNow = ordersTillNow + 1 ")) 
{
    connection.Open();
    command.Connection = connection;

    command.ExecuteNonQuery();
    connection.Close();
}

I’ve tried to put that statement into SQL Server Management Studio – and that works. Why does my C# not change the value?

Answer 1

Your forgot:

connection.Open();

In the end your code should look like this:

using (SqlConnection connection = new SqlConnection("..."))
using (SqlCommand command = connection.CreateCommand())
{
    command.CommandText = "...";

    connection.Open();

    command.ExecuteNonQuery();
} // will close the connection automatically

And note:

using-block against SqlConnection is much more important then against SqlCommand.