Materialized view maintenance for XML documents

Abstract

XML views are often materialized for improving query performance. Their consistency needs to be maintained against the updates of the underlying source data. In this thesis, we propose an approach to incrementally maintain the materialized view for XML documents based on a semantically rich data model a?? ORA-SS. This approach introduces a new concept a?? update tree to identify the changes to source and view. It can detect the invalid source update queries, which will make the XML inconsistent. The view update tree will be computed based on the valid source update tree, and be merged into the existing materialized view tree to produce the complete updated view. This approach supports more complex XML views than other works, such as views involving swap, join and aggregation of source data. We also define a set of update operations with the XQuery syntax, which can be updates on both single element/attribute and subtree.