Updating Recursive XML Views of Relations

This paper investigates the view update problem for \sc XML viewspublished from relational data. We consider \sc XML views definedin terms of mappings directed by possibly recursive \sc DTDscompressed into \sc DAGs and stored in relations. We provide newtechniques to efficiently support \sc XML view updates specified interms of \sc XPath expressions with recursion and complex filters.The interaction between \sc XPath recursion and \sc DAG compressionof \sc XML views makes the analysis of the \sc XML view updateproblem rather intriguing. Furthermore, many issues are still open evenfor relational view updates, and need to be explored. In response tothese, on the \sc XML side, we revise the notion of side effects andupdate semantics based on the semantics of \sc XML views, and presentefficient algorithms to translate \sc XML updates to relational viewupdates. On the relational side, we propose a mild condition on \sc SPJviews, and show that under this condition the analysis of deletions onrelational views becomes PTIME while the insertion analysis is NP-complete. We develop an efficient algorithm to processrelational view deletions, and a heuristic algorithm to handle viewinsertions. Finally, we present an experimental study to verify theeffectiveness of our techniques.