Research On The Problems Of XML Query And Updatting Based On Security View

With more and more data are represented and transferd by XML, XML is becoming a new Web language, the security of XML documents has become very important. In order to prevent user from inferring sensitive data in XML documents by using published data, this paper uses Security View which is based on access control mechanism to prevent sensitive data disclosure. In the meantime, in order to satisfy user's need for updating, it proposes Security View updating system.Firstly, this paper analyses sematic constraints in XML documents and illustrates how to infer data by using these constraints. To prevent sensentive data disclosure, it proposes XML Security View definition language SSX. Security Annotated Schema SAS can be constructed through sentences written by SSX, it can be used to transform user's XPath over Security View into XQuery over data source, so the cost by view materialization is avoided. Security View is provied to authorized user, user can formulate and pose queries on Security View, however, XML original documents and sematic constraints in XML documents are invisible to user, so sensentive data in data source are efficiently protected.Secondly, to further improve the efficiency of rewrited XQuery, this paper uses GTP to represent XQuery, it uses semantic constraints in DTD of XML documents to optimize GTP, so the efficiency of query is improved.Thirdly, this paper proposes XML Security View updating system to solve the updating problem. It expands XQuery so that XQuery can support updating on XML documents. Security View updating system can transform uer's updating over Security View into updating over data source. To guarantee the validity of updating, it proposes checking rules based on DTD.Finally, based on research results above, this paper approves the feasibility, effectiveness of these approaches through experiments.