The concentration of industry on modern relational databases has left many nonrelational and proprietary databases without support for integration with new technologies. Emerging interface tools and data-access methodologies can be applied with difficulty to medical record systems which have proprietary data representation. Users of such medical record systems usually must access the clinical content of such record systems with keyboard-intensive and time-consuming interfaces. COSTAR is a legacy ambulatory medical record system developed over 25 years ago that is still popular and extensively used at the Massachusetts General Hospital. We define a model for using middle layer services to extract and cache data from non-relational databases, and present an intuitive World-Wide Web interface to COSTAR. This model has been implemented and successfully piloted in the Internal Medicine Associates at Massachusetts General Hospital.