In this dissertation, we address integrity constraints for access control of XML documents and propose two element-wise access control methods for XML documents. First, we propose an access control method of XML based on relational database. Some merits of XML data stored in relational databases are as follows: the compatibility of XML data with traditional relational data; the utilization of advanced relational database technologies. In this dissertation, we focus on access control of ordered XML data stored in relational databases. Second, we propose an access control method that filters access-granted XPath expressions from the query XPath expressions. To filter the access-denied part out of the query XPath expressions, set operations (union, intersection and difference) among the XPath expressions are essential. We show query XPath expressions are successfully filtered through the XACTr by our proposed method.