Schema Evolution publication categorizer

XML documents are a typical kind of semistructured data. The usage of XML has increased significantly since 1998, when the XML recommendation was released. The structure of XML documents can be described using a Document Type Definition (DTD). Documents are called valid documents if their structure corresponds to a DTD. If the structure of a DTD changes, it is desirable to apply these changes to documents that are valid with respect to this DTD. These transformations are called evolution. This paper shows how different changes to the DTD effect XML documents. The focus will be on the question what kinds of transformations are possible and to which conditions they are bound especially to preserve the validity of the documents and to minimize data loss. Furthermore, this paper presents a draft of a system architecture for transforming DTDs and XML documents valid to these DTDs using XSLT. Finally, some transformations are described using an appropriate data model.