Using statement - is this more useful for the sql connection than the sql adapter?

Question

I know that the following statement is useful for garbage collection. Effectively it must be the same as Try/Catch/finally. If I use it for the sql connection should i also nest a further 'using' statement for a sql adapter? And then a further nested using for the DataSet?

using()
{
} 

A further addition to the question is if I want to use the same connection across several methods then is it best practice to have 'Using()' in each of the methods, or can I just create this connection object once?

Answer 1

Something else that is worth pointing out is that you can combine multiple using statements into one block like this:

using (SqlConnection connection = new SqlConnection("connectionString"))
using (SqlCommand command = new SqlCommand("SELECT * FROM Users", connection))
{
    // Do something here...
}

Once you exit this block (either by reaching the end of the block or an exception was thrown), both the SqlConnection and SqlCommand object would be disposed automatically.