Single Transition Constraint for XML Update Validation

In this paper, we propose a checking algorithm for dynamic constraint validation during XML updates. Our algorithm is targeted at single transition constraint, which is affected by single node updating. To the best of our knowledge, almost all constraints that have been preserved in the previous XML updates works are for static constraints. On the other hand, dynamic constraints restrict the transition of data from a current state into a new state. The operations that can affect these constraints involve node replacement, value of element and attribute replacement, and insert-delete pairing operations of nodes and their values. We propose a lightweight XML file to store only required data for the validation, i.e. states that need to be changed are extracted from XQuery and original XML documents. For experimentation purposes, we apply the algorithm in Java platform with the support of Schematron for the dynamic constraint and BaseX for parsing XQuery statements. The analysis shows our algorithm performs in cubic growth while still in polynomial efficiency. Nevertheless, our proposed dynamic constraint file is not minimal enough if the query involves indirect states transitions caused by sub queries. We would like to continue and extend the work with more types of dynamic constraint.