Can you use water base primer over oil base paint before top coating with latex paint?

You can always paint latex ( water based )over an oil based paint as the latex just dries on the surface. However don't paint an oil based over a latex paint. Oil based paints need to absorb into the wood or other surfaces or it will just dry and flake off. For more information on the differences and when or not to use a latex or oil paint please see the following article. .

http://www.ehow.com/how_4713170_between-latex-oil-base-paint.html