[R] deciphering help for `attach`

[Edward McNeil]

Hi,
I have two related questions.

1. In the help page for `attach` under "Details" it says in paragraph 3:
"By default the database is attached ..."

But then paragraph 4 starts: "The database is not actually attached."

Could somebody explain this contradiction? Is the data(base) attached or not?

2. What is meant by the 5th paragraph: "One useful ‘trick’ is to use what = NULL (or
equivalently a length-zero list) to create a new environment on the search path into
which objects can be assigned by `assign` ... "?

I don't understand what this "trick" is or why a "trick" needs to be performed here.

Thanks
-- 
Edward McNeil