Integrity Constraints in Spatial Databases

INTRODUCTION A number of integrity constraints must be observed when updating a database, to preserve the semantics and the quality of stored data (Elmasri & Navathe, 2000). Achieving and preserving the integrity of data is an established field in the database area. However, within the scope of geographic applications, special problems come up due to the locational aspects of data (Plumber & Groger, 1997). Most geographical information systems (GIS) use data that depend on topological relationships, and sometimes these data must be explicitly represented in the database, requiring special attention for the maintenance of the semantic integrity. Enforcing the integrity constraints must be considered one of the main implementation goals (Borges et al., 1999). Thus, it is convenient to explicitly specify on the geographic application schema the situations where the constraints cannot be disregarded. Many mistakes in the data entry process could be avoided if digitizing processes based on these constraints were implemented.