Gram(ID:5558/gra007)A Graph Data Model and Query Language References: Regular expressions over the types of the node and edge labels are used to qualify connected subgraphs. An algebraic language based on these regular expressions and supporting a restricted form of recursion is introduced. A natural application of this model and its query language is hypertext querying. Extract: Introduction Recent database research work shows a growing interest in the definition of graph models and languages to allow a natural way of handling data appearing in applications such as hypertext or geographic database systems. Standard data models are often inefficient as they do not capture the inherent structure of data representing hypertext documents or networks (highways, rivers,...). In this paper, we present a graph data model. Its application to hypertext querying is illustrated by an example of a travel agency that organizes journeys. We think of a hypertext as a directed labeled graph where the nodes are typed documents and the edges correspond to typed span-to-span links between documents. |