|
|
 DTD Transformation by Patterns and Contextual Conditions
Paper presented at SGML/XML'97 (12/8, 1997) This presentation shows transformations of DTD's and XML documents. Each operator transforms not only XML documents, but also DTD's. The output instances are guaranteed to conform to the output DTD's. Furthermore, the output DTD's are minimally sufficient; in other words, they allow only those XML documents which may be generated. Operators are controlled by patterns and contextual conditions. Patterns are conditions on (possibly non-immediate) subordinate nodes, and contextual conditions are conditions on non-subordinate nodes (e.g., superior nodes, ancestor nodes, sibling nodes, and subordinates of sibling nodes). Such DTD transformation is highly important for at least reasons. First, it helps DTD evolution; by writing an update program with operators, we can update not only instances but also DTD's. Second, transformation among different DTD's become a lot easier; we can examine DTD's created by transformation operators. This work is based on the theory of tree automatons. A DTD is first translated to a tree automaton. This tree automaton is then repeatedly transformed. Finally, this tree automaton is translated back to a DTD. Patterns and contexual conditions of operators are also captured as tree automatons. In this presentation, we demonstrate an example of DTD transformation rather than providing theoretical details.  | This paper is important because it addresses both hedge automata (a very recent entry into the XML Schema effort) and their application to managing the process of schema evolution. |  |
Researchers that authored this literature
|
Explore >