An introduction to Graph Data Management

A graph database is a database where the data structures for the schema and/or instances are modeled as a (labeled)(directed) graph or generalizations of it, and where querying is expressed by graph-oriented operations and type constructors. In this article we present the basic notions of graph databases, give an historical overview of its main development, and study the main current systems that implement them

Verso: A data base machine based on non 1NF relations

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The Semantics Of The Geographical Database Query Languages

: In this paper, we analyze the various philosophies to define a query language for geographical database. The differences among the three possibilities of extending the SQL language rely on the definition of the clause Select: (1) the clause Select does not accept a spatial operator and the Where clause accepts one (or several) predicate defined between attributes; (2) the clause Select accepts one (or several) spatial operator(s) with attributes as arguments; (3) the clause Select accepts one (or several) spatial operator(s) with attributes or other spatial operators as arguments. To guarantee a coherent result of a query, we present the requirements of these three philosophies. Key words: Geographical Information System, Spatial Database, Query Language, Extended SQL I. INTRODUCTION In the current research toward the design of more powerful tools for urban planning, remote sensing, ... different research groups are simultaneously concentrating their work on Geographical Informatio..