A SQL extension to support advanced spatial data types and integrity constraints

Abstract

Geometric primitives defined by OGC and ISO standards, implemented in most modern spatially-enabled DBMS, are unable to capture the semantics of richer representation types, as found in current geographic data models. Moreover, relational DBMSs do not extend referential integrity mechanisms to cover spatial relationships and to support spatial integrity constraints. Rather, they usually assume that all spatial integrity checking will be carried out by the application, during the data entry process. Therefore, this work presents AST-PostGIS, an extension for PostgreSQL/PostGIS that incorporates advanced spatial data types and implements spatial integrity constraints. The extension reduces the distance between the conceptual and the physical designs of spatial databases, by providing richer representations for geo-object and geo-field geometries. It also offers procedures to assert the consistency of spatial relationships during data updates.