has written an interface to the Berkeley DB v4 database
Alain Picard has now ported it to LispWorks! And David Lichteblau has ported it to Allegro Common Lisp (ACL).
It is available from http://users.actrix.co.nz/mycroft/cl.html.
Clisp (v2.33 and later) comes with an extension module for interfacing with a berkeley-db database.