This paper has studied the consistency problem for XML-Data schema in terms of XML-Data schema hedge as well as keys and foreign keys. The consistency problem is to check whether there exists an XML-Data schema hedge that both conforms to the schema and satisfies integrity constraints. Definitions of XML-Data schema and XML-Data schema hedge for the purpose of investigating this problem are proposed

moreover

an algorithm for constructing the XML-Data schema hedge from a given XML-Data schema is given. The undecidability of the consistency problem for XML-Data schema is also presented.