ABSTRACT
Clinical research involves recording, storage and retrieval of disease-related patient data, typically using a database system. In order to facilitate ad hoc queries to clinical databases we have developed a query generator with a graphical interface. The query generator uses an object-oriented data model which is visualized by directed graphs. The main focus of our work was the definition of object-oriented user views to the partly complex data structures of a relational database. Furthermore, we tried to define graphical abstractions for all common types of queries. Thus, even for non-expert database users such as clinicians, it is easy to assemble highly complex queries for a thorough examination of the content of large research databases.
