It is well-accepted that there is a need to incorporate domain knowledge into system development tools of various kinds. Most of these are case tools that have been quite successful in supporting design on a syntactical basis. However, in general, they are not capable of representing and using information about the semantics of an application domain. This research presents a framework for supporting the generation and analysis of conceptual database designs through the use of ontologies. The framework is implemented in a database design assistant prototype that illustrates the research results.