Detecting changes on unordered XML documents using relational databases: a schema-conscious approach

Several relational approaches have been proposed to detect the changes to XML documents by using relational databases. These approaches store the XML documents in the relational database and issue SQL queries (whenever appropriate) to detect the changes. All of these relational-based approaches use the schema-oblivious XML storage strategy for detecting the changes. However, there is growing evidence that schema-conscious storage approaches perform significantly better than schema-oblivious approaches as far as XML query processing is concerned. In this paper, we study a relational-based unordered XML change detection technique (called H<small>ELIOS</small>) that uses a schema-conscious approach (Shared-Inlining) as the underlying storage strategy. H<small>ELIOS</small> is up to 52 times faster than X-Diff [7] for large datasets (more than 1000 nodes). It is also up to 6.7 times faster than X<small>ANDY</small> [4]. The result quality of deltas detected by H<small>ELIOS</small> is comparable to the result quality of deltas detected by X_ANDY.