U-Filter: A Lightweight XML View Update Checker

We study in this paper the problem of whether a correct relational update translation can be found for a given update over an XML view. For this, we propose a lightweight update checking framework named U-Filter. It first performs two steps of schemalevel (and thus very inexpensive) checks based on a view definition analysis. Only when necessary, a third checking step, requiring base data access and thus more expensive, is employed. For the latter, we design an internal strategy as well as an external strategy (with respect to the DBMS). This three-step checking process is guaranteed to filter out all XML updates that cannot be translated. Finally, the remaining updates are fed to the update translation engine, which generates the corresponding SQL update statements. Our experiments illustrate the usefulness of U-Filter and the performance impact achievable by the proposed algorithm