Report Number: CS-TR-96-1565
Institution: Stanford University, Department of Computer Science
Title: A Formal Model for Bridging Heterogeneous Relational Databases in Clinical Medicine
Author: Sujansky, Walter
Date: April 1996
Abstract: This document describes the results of my thesis research, which focused on developing a standard query interface to heterogenous clinical databases. The high-level goal of this work was to *insulate* the developers of clinical computer applications from the implementation details of clinical databases, thereby facilitating the *sharing* of clinical computer applications across institutions with different database implementations. Most clinical databases store information about patients' diagnoses, laboratory results, medication orders, drug allergies, and demographic background. These data are valuable as the inputs to computer applications that provide real-time decision support, monitor the quality of care, and analyze data for research purposes. Clinical databases at different institutions, however, vary significantly in the way the databases model, represent, and retrieve clinical data. This database heterogeneity makes it impossible for a single computer application to retrieve data from the clinical databases of various institutions because the database queries included in the application must be formulated differently for each institution. Therefore, database heterogeneity makes it difficult to share computer applications across institutions with different database implementations. In my work, I have developed an *abstract* model of clinical data and an *abstract* query language that allow the developers of computer applications to formulate queries independently of the institution-specific features of clinical databases. I have also developed a database mapping language and a formal query-translation method that automatically translate the abstract queries that appear in applications into equivalent institution-specific queries. This framework ostensibly allows copies of a single computer application to be distributed to multiple institutions and to be customized automatically at each of the institutions such that the queries in each copy of the application can retrieve data from the local clinical database. This dissertation formally describes the abstract data model, the abstract query language, the mapping language, and the translation algorithm. It also presents the results of a formal evaluation that I performed to assess the feasibility and utility of this approach for sharing clinical computer applications.