Do you need an external midi source to use sonar or can you create music with your mouse?

Thanks. I looked all over the internet to try and find the answer to my question and couldn't find it. I dont have any of the SONAR programs and i am tryig to decide between SONAR X1 essential and ACID Music Studio 8.

Even though I use a guitar-midi interface as my primary input, I use the piano roll view quite a bit, not only to edit the inevitable  false triggers that pitch to midi creates, but also as an alternative to the inadequate staff entry.  As one who began using notation extensively, and exclusively, I've actually come to prefer the piano roll.  If you have a good sense of what you want to hear in your head, you can transcribe it pretty much exactly using PRV.  I've come to think of notation as an old and cumbersome technology, since with PRV, you can actually enter things that are very difficult to transcribe on a staff, assuming the software will let you.