DTD-Diff: A change detection algorithm for DTDs

The DTD of a set of XML documents may change due to many reasons such as changes to the real-world events, changes to the user’s requirements, and mistakes in the initial design. In this paper, we present a novel algorithm called DTD-Diff to detect the changes to DTDs that defines the structure of a set of XML documents. Such change detection tool can be useful in several ways such as maintenance of XML documents, incremental maintenance of relational schema for storing XML data, and XML schema integration. We compare DTD-Diff with existing XML change detection approaches and show that converting DTD to XML schema (XSD) (which is in XML document format) and detecting the changes using existing XML change detection algorithms is not a feasible option. Our experimental results show that DTD-Diff is 5–325 times faster than X-Diff when it detects the changes to the XSD files. Compared to XyDiff, DTD-Diff is up to 38 times faster. We also study the result quality of detected deltas.