A Constraint-based Spatial Extension to SQL

The constraint database model provides a uniform framework for handling spatial and non-spatial data. We describe our proposal for a query language for GISs based on this model. Our language is called CSQL, as it is based on SQL. CSQL provides the full query capabilities of SQL on the non-spatial part of the database while being tightly integrated with the spatial part. This allows us to optimize CSQL queries in a unified fashion, considering both the spatial and non-spatial attributes simultaneously. We are in the process of implementing a constraint database system using CSQL as a query language, via a relational algebra CALG, and an extensible database system. 1 Introduction The constraint database model [6] is an active area of research in the database community. The key notion of the model is to generalize the notion of a tuple to a conjunction of constraints, e.g., linear arithmetic constraints. It turns out that the relational algebra and calculus can be naturally extended to ..