Are composite and component cables really interchangeable?

Hi, I was told to open up a new thread for this so please ignore the older one.

I see there are many opinions on this subject so I just want to confirm with a little more detail. If I have a VGA to component (red, green, blue) cable or a DVI to component cable, can I do the following: VGA out from computer to composite TV in using component red to composite red, component green to composite white, and component blue to composite yellow?

Also, the same connection using a DVI to component cable.

I presume there will be a quality decline but not so much as I don't actually require a true digital quality video. I am happy with the analog quality so I just want to be sure this will work before I purchase these cables.