Advanced technical applications like routing systems or electrical network managementsystems introduce the need for complex manipulations of large size graphs. Efficiently supporting this requirementis now regardedas a key feature of future databasesystems. er proposesan abstraction mechanism,called Database Graph View, to define and manipulate various kinds of graphs stored in either relational, object oriented or file systems. A databasegraph view provides a functional definition of a graph which allows its manipulation independently of its physical organization. Derivation operators are proposed to define new graph views upon existing ones. These operators permit the composition, in a single graph view, of graphs having different node and edge types and different implementations. The graph view mechanism comes with an execution model where both set-oriented and pipelined execution of graph operatorscan be expressed. The graph view operators form a library which can be integrated in...