The usage of the `using` statement in C# when dealing with Database related classes the best practice?

Question

The using statement automatically execute the Dispose method contained in IDisposable, database related classes (like SqlConnection, SqlCommand, etc) implement this interface.

So if I going to use this sort of classes should I use a using statement for the objects creation so the resources will be released at operation end?

For example, I need to use a SqlConnection, SqlCommand, SqlDataAdapter and a DataTable for some reason so I write this code below, is this the best way to do so or should I put the Dispose() at the finally clause of a try... catch... finally?

using (SqlConnection con = new SqlConnection(Properties.Settings.Default.ConnectionString))
using (SqlCommand cmd = new SqlCommand())
using (SqlDataAdapter da = new SqlDataAdapter())
using (DataTable dt = new DataTable())
{
    // Do something...
}

Answer 1

The way you have it is correct. The Dispose() methods will automatically call Close(). That's not necessarily true for everything that implements IDisposable, but for the DB-related classes, it is.