How to delete a installed software ?

hi
my problem is that i have installed a software named oracle .the size of the software is 2.7gb .
after installing it i checked the property of the software .it shows the size as 12.5gb.so i thought to delete it.
i pressed shift+delete to delete it.but its of no use.
so will u plz tell me how to delete it .if any software required please tell the name of it.