Research And Implementation Of XML Storage Based On Relational Database And Object-Oriented Method

At present, the development pattern which transmitting data by XML, designing business logics based on 00 (Object-oriented) and storing final data into RDB (Relational Database) has become a dominant pattern in the software field. From the XML pattern to the object pattern, then to the relational pattern, the data format is changing all along. XML is hierarchical and self-described. XML has its own schema and criterion, as well as programming interface. Object is instanced from class, and it describes things by the attributes and methods of a class. RDB stores data in flat and two-dimensional tables. During the transformation, how to maintain the data integrity and make use of it conveniently has become a bottle-neck in the software development process.Previous research concentrates on one-off transformation between one XML and RDB, which fails to associate with the 00 development process tightly. This results in a complex table structure and awkward relation between tables. However, in practical applications, in order to rebuild one or many new XML documents for other system, we often need to append some operations on the multi-copy transformed XML data, such as delete, update, select, and combination. Moreover, they only store the structure and content, and ignore the semantics, which makes maintaining data difficultly.In order to solve the problem, 00 and UML modeling method has been applied when parsing XML. Firstly the XML is transformed to object pattern, and then is stored into RDB according to the Object-Relation mapping method. The mapping method from XML to object, then to relation pattern has been mainly researched, and a kind of meta-table storage model has been taken to store data.Triggers have been applied to maintain XML semantics. The persistence layer of the system is extended to encapsulate the XML operations, thus the business layer can conveniently manipulate the XML object data in a way of object manipulation. For example, we can update and rebuild new XML documents in object model, and the results can be reflected on database in time.Based on the research above, an XML storage prototype XOR (XML-Object-Relation) has been designed and implemented, it can be customized to store and rebuild XML documents. At last, the performance test results of XOR are given.