A Fuzzy Extension for the XPath Query Language

Today the current state of the art in querying XML data is represented by XPath and XQuery, both of which rely on Boolean conditions for node selection. Boolean selection is too restrictive when users do not use or even know the data structure precisely, e.g. when queries are written based on a summary rather than on a schema. In this paper we describe a XML querying framework, called FuzzyXPath, based on Fuzzy Set Theory, which relies on fuzzy conditions for the definition of flexible constraints on stored data. A function called “deep-similar” is introduced to replace XPath’s typical “deep-equal” function. The main goal is to provide a degree of similarity between two XML trees, assessing whether they are similar both structure-wise and content-wise. Several query examples are discussed in the field of XML based metadata for e-learning.