You might be interested in looking at this FREE White Paper from Oracle on this subject. Their blurb says:
Strengthening internal controls for regulations, enforcing industry best practices, and guarding against insider threats are just a few of the challenges facing organizations in today’s global economy. While problems such as the insider threat are certainly not new, the concern over unauthorized access to sensitive information has never been greater. Transparent security controls are critical when bringing existing applications and IT operations into compliance with existing and newly emerging regulations as well as industry best practices. This white paper discusses a database security solution that provides flexible, transparent and highly adaptable security controls with no application changes necessary.
The Link: http://www.itbusinessedge.com/offer.aspx?o=00300067em1014