A "return on investment" digital database usage metering, billing, and security system includes a hardware device which is plugged into a computer system bus (or into a serial or other functionally adequate connector) and a software program system resident in the hardware device. One or more databases...http://www.google.ca/patents/US4977594?utm_source=gb-gplus-sharePatent US4977594 - Database usage metering and protection system and method
