Abstract: The management technology of uncertain XML database becomes today’s research focus with XML being the standards of information representation and data exchange on the Internet and uncertain data existing in various fields.Firstly,the leaf nodes’ information value of XML document being lost or missing null values was allowed and the incomplete XML information system was proposed.Secondly,the definitions of node tolerance relation,limited tolerance relation and threshold tolerance relation were given,and three kinds of rough set models for incomplete XML information system were defined respectively based on rough set theory.Finally,the analysis of examples shows that limited tolerance relation can overcome the disadvantage of tolerance relation rough classification,and threshold tolerance relation can achieve better classification results through reasonable threshold setting,so as to enhance the prediction and the classification accuracy of XML data.

Key words: Rough set,Incomplete XML information system,Tolerance relation,Limited tolerance relation,Threshold value tolerance relation