Integration of XML data

Various XML instances from different data sources can model the same object of the real world. Query processing or view definition over these sources demands instance integration. In this context, integration means to identify which data instances represent the same object of the real world, as well as to solve ambiguities of representation of this object. The entity identification problem in XML is more complex than in structured databases. XML data, as originally considered, necessarily do not have the identification notion of primary key or object identifier. Thus, it is necessary the adoption of a mechanism that identifies the instances at the moment of data integration. This paper presents a proposal for identifiers attribution to XML instances, based on the use of Skolem functions and XPath recommendation, as proposed by W3C.