Basic question abount apt install

["Alex Kwan" <alexkwan@pacific.net.hk>]

Hi!

(1) If I use apt-get to install a package, the package's name is simple or
full?
apt-get install apache or apt-get install apache_1.3.12-1.deb ?

(2) If I only want to upgrade a package not whole system,
Is the command "apt-get upgrade package" or
"apt-get install package_newversion.deb"?

Thanks