Research On Key Issues Of Integrity Constraints About XML Documents

As XML has become the standard of information expression and exchange, it is more and more widely used with the application of XML. At present, many researchers have done many researches on XML database. It can be devided into two types: Enable XML database and Origin XML database. The former one is to change the XML data into matured database skill to deal with, such as Relational Database, Object-Oriented Database,etc. The latter one is to cope with XML straightly. However, there are only few theoretical studies in XML document integrity controls based on these two types. Therefore, this paper studies several key problems in the XML document integrity controls.To counter the features of XML tree structure, the definition of XML function reliance is put forward based on the path. The corresponding inference rule is introduced. This paper introduces the way to work out setting path closure and memberships of members, and analyzes the correctness,termination and time complexity, pointing out the definition of XML button and Candidate button and the algorithm of the XML local candidates key finally.The definition of XML and more dependency based on he concept of tree tuple group is introduced. Based on the concept of reliance of the set of XMVD path and closure of the set of XMVD path, the algorithm of reliance of the set of XMVD path and XMVD memberships of members is displayed.This paper introduces the concept of a paradigm for X1NF, X2NF, X3NF to counter the XML DTD model. Making the use of DTD lossless connection decomposition and standardized rules, DTD is introduced to nondestructive connection with the decomposed into X2NF, X3NF algorithm. This paper analyzes the correctness, termination and the time complexity of and through examples of this standardized algorithm of testing the correct application to achieve the purpose of standardization. The XML documents' research is one of the fields which has prospects, therefore many computer experts hold the very high expectation to its prospects. As a result of time and condition limit, this paper only discusses the function dependency, multiple-valued dependency in the XML documents, studying the model based on XML button and Candidate button. To solve the update anomaly and data redundancy questions which are caused by part of function dependency and transfer function dependency in the XML documents,making the use of DTD lossless connection decomposition and standardized rules, DTD is introduced to nondestructive connection with the decomposed into X2NF, X3NF algorithm ,this research carrys on the standardization to DTD which promotes the study of the standardization of the XML documents. However, a large amount of work should be studied and extended in depth in this field in the future.