Do I need to do an "apt-get update" after adding a PPA?

view full story

http://askubuntu.com – After adding a new ppa to the repository, is it necessary to update the whole database? By "whole database" I mean is it necessary to update index's of each and every packege? If it's not necessary, then how can I update only that specific package whose ppa I have just added into the repository. For example, if I add an ppa by typing the following in terminal, sudo add-apt-repository ppa:tiheum/equinox then we normally run the following command after it, sudo apt-get update But how can I update the only package which is associated with the above ppa, instead of updating the whole data (HowTos)