Rasters, Vectors and spatial databases

Hi!
I'm working on writing some programs to analyse raster datafiles. So
far, I have used gdal to load up the rasters. In order to carry out
our analyses, we have downloaded from an Oracle Spatial database, the
locations and atributes of a number of polygons, which have been
subsequently rasterised to cover the same region and cell spacing as
the rasters which we want to analyse. This works, and works pretty
well. However, I would like to automatise that, because the data in
the database changes every so often. Ideally, I would like to just
point the program to the database and let it get the data, generate
the vectors and carry out the pixel selection.

I'm not familiarised with the libraries that might be used to
accomplish this. I would appreciate views on how to accomplish this
(in its totality or even in parts!), what free sofware options are
available, etc.

Many thanks for your time,
Jose