A new method for providing integrated support for multiple development notations (including analysis, design, and implementation) within Information Systems Engineering Environments (ISEEs) is described. Our method supports both static integration of multiple notations and the implementation of dynamic support for them within an integrated ISEE. First, conceptual data models of different analysis and design notations are identified and modelled, and then merged into an integrated conceptual data model. Second, mappings are derived from the integrated conceptual data model, which translates data changes in one notation to appropriate data changes in the other notations. Third, individual ISEEs for each notation are developed. Finally, the individual ISEEs are integrated via an integrated repository based on the integrated conceptual data model and mappings. An environment supporting integrated tools for Object-Oriented Analysis and Extended Entity-Relationship diagrams is described, which has been built using this technique.