In an org file, I want the category of each item (and subitems) to be
the name of the first level heading, is there a way to do this without
setting the category for each heading like so?:

* Web
  :PROPERTIES:
  :CATEGORY: Web
  :END:
** Web1
** Web2
* Holiday
  :PROPERTIES:
  :CATEGORY: Holiday
  :END:
** Holiday1
** Holiday2


Best wishes,

Enda


P.S. In the org manual on page 95, there is

* Birthdays and similar stuff
#+CATEGORY: Holiday
%%(org-calendar-holiday) ; special function for holiday names
#+CATEGORY: Ann
%%(org-anniversary 1956 5 14)6 Arthur Dent is %d years old
%%(org-anniversary 1869 10 2) Mahatma Gandhi would be %d years old

Is using #+CATEGORY: like this depreciated according to the footnote
on page 101 of the org manual?