Using Constraints to Manage Long Duration Transactions in Spatial Information Systems

A constraint-based long duration transaction model for spatial information systems is proposed in this paper. The model, called the COLT (COnstraint based Long Transaction) model, is a generalisation of the traditional ACID transaction model. Its behaviour is governed by user-deened correctness criteria. Constraints are used both to manage the long duration transactions and to specify the correctness criteria. This approach enables the speciication of the correctness criteria to be declarative. Furthermore, the user needs to have no knowledge of the semantics of other concurrently executing transactions. The COLT model is formally speciied using the external actions of the I/O automata method and correctness is deened with respect to that method. That is, correctness is deened independent of implementation. This paper also discusses some implementation issues.