Database Graph Views: A Practical Model to Manage Persistent Graphs

Advanced technical applications like routing systems or electrical network management systems introduce the need for complex manipulations of large size graphs. Efficiently supporting this requirement is now regarded as a key feature of future database systems. This paper proposes an abstraction mechanism, called Database Graph View, to define and manipulate various kinds of graphs stored in either relational, object oriented or file systems. A database graph 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 operators can be expressed. The graph view operators form a library which can be integrated in database systems or applications managing persistent data with no repercussion on the data organization.