A Logical, Transparent Model for Querying Linked XML Documents
Wolfgang May and Dimitrio Malheiro
The W3C XML Linking Language (XLink) provides a powerful means for interlinking XML documents all over the world. While the effects when browsing through linked XML documents are well-defined, there is not yet any proposal how to handle interlinked XML documents that make use of the XLink language from the database point of view, i.e., considering the data model and navigation/querying aspects. From the database (and in general, querying) point of view, elements with linking semantics can be seen as virtual XML subtrees, i.e., XML views. Compared with classical databases, i.e., SQL and relational data, the situation of having links inside the data is new. We define a logical, transparent data model for linked documents. Queries are then formulated in standard XPath against the logical model. We propose additional attributes using the dbxlink (database-xlink) namespace for specifying the mapping from XLinks to the logical model.