XEM: XML Evolution Management
Diane S. Kramer · Digital WPI · 2001
As information on the World Wide Web continues to proliferate at an astounding rate, the Extensible Markup Language (XML) has been emerging as a standard format for data representation on the web. In many application domains, specific document type defini-tions (DTDs) are designed to enforce a semantically agreed-upon structure of the XML documents. In XML context, these structural definitions serve as schemata. However, both the data and the structure (schema) of XML documents tend to change over time for a multitude of reasons, including to correct design errors in the DTD, to allow expansion of the application scope over time, or to account for the merging of several businesses into one. Most of the current software tools that enable the use of XML do not provide explicit support for such data or schema changes. Using these tools in a changing envi-ronment entails making manual edits to DTDs and XML data and reloading them from scratch. In this vein, we put forth the first solution framework, called XML Evolution Manager (XEM), to manage the evolution of DTDs and XML documents. XEM provides a minimal yet complete taxonomy of basic change primitives. These primitives, clas-