Ginger is right - this is a simple question with very complex answers. For the quickest insight into a non-cast- in-place system that is technically and economically appropriate for your site, you should contact a specialty geotechnical contractor in your area who designs/builds a lot of walls.
Mdrotar is exactly correct. It is necessary to specifically evaluate the actual nature of the rock formation at those locations where it will support the shallow foundations. It is possible to have a relatively porous rock condition which might permit the penetration of water into the foundation...
