This paper introduces a graph-oriented model for conceptual level design of large, complex information systems. This has been shown to be highly effective to the system designer from the perspectives of maintainability and upgradability. Due to the flat structure and the lack of holding multidimensional data, the relational model does not provide a structural approach to the system designer. The other alternative object oriented model offer the structured approach but also not able to describe various intermodular relationships spread over same or different levels within a data model. The graph data model also allows dynamic regrouping of related entities at the designers' level. We have proposed the appropriate data structure and corresponding DDL has also been developed. Test runs on simulated environment further establish its computational efficiency.