Object Relational Constraint Databases for GIS

Abstract

Constraint databases (CDBs) have been used in geographical information systems as a mechanism to represent the complex objects and information that can participate in this type of application. CDBs are proposed to represent geographical data by means of formulas described by constraints (equations, inequations, or Boolean combinations of both), since classic data types lack the expressiveness required for the representation of the full domain of data. The appearance of the object-relational constraint databases (ORCDB) was an evolution of the definition and implementation of CDBs to optimize query evaluation. ORCDBs enable complex information represented by means of constraints to be stored and queried in object-relational databases. This evolution shields the user from unnecessary details on how the complex information is stored and how the queries are evaluated, thereby enlarging the capacity of expressiveness for any commercial database management system.