Orthogonality in DBMS Design: the XML Approach
Lutz Wegner, Morad Ahmad · 2001
Abstract. XML, XML-Schema and the style sheet language XSL have emerged as a base for universal data exchange. They have enriched our capabilities for view generation and schema transformations. Mapping hierarchical documents into tables according to the nested relational model is one obvious example. One elegant way to achieve this is to augment the document’s schema, given e.g. as XSD-document, with attribute definitions which force the appearance of certain attribute values (types) for certain tags in the document. This saves work in the document preparation, makes them less error-prone and more readable. It also gives rise to generic style sheets which can display any data whose schema obeys the simple type rules. With schemas and style sheets being XML-documents in their own right, the questions of meta-schema and metavisualization must be addressed as well. Examples in this paper show that solutions can be found for all of these problems within the XML approach. 1 XML and the Nested Relational Model Research into the so-called Non-First Normal-Form (NF 2) data models [15] in the