Evaluation of an object-based data model implemented over a proprietary, legacy data model.

Most computerized medical information today is contained in legacy systems. As vendors slowly move to open systems, legacy systems remain in use and contain valuable information. This paper evaluates the use of an object model imposed on an existing database to improve the ease with which data can be accessed. This study demonstrates that data elements can be retrieved without specific programming knowledge of the underlying data structure. It also suggests that underlying data structures can be changed without updating application code. Programs written using the object model were easier to program but ran greater than one order of magnitude slower than traditionally coded programs. In this paper, the legacy information system is introduced, the methods used to implement and evaluate the object-based data model are explained, and the results and conclusions are presented.