Locating patient data among multiple heterogeneous medical databases

The general problem of connecting heterogeneous databases is well understood. The paper considers the problem from the perspective of medical databases where particular information can be expected to be fragmented over a number of separate databases and where the types of queries would generally be patient-centred. Several different options for structuring data are considered and analysed in terms of their effect on performance. An architecture is proposed and its implementation described briefly. The approach has been used to connect together Ingres and Oracle databases. © 1993.