| 摘要 |
The present invention provides a technique by which complex queries can be defined and executed in a very flexible and efficient manner. It allows user to define the relationships between a parent and its different children, which can be nested to n-depth levels. The relationships are mapped to a special tree structure and the query processor executes the query based on t he tree in an efficient way. The output data is also constructed in the defined tree structure in XM L by default, which eliminates data redundancy. The output can be formatted either in Extensible Markup Language (XML) or HyperText Markup Language (HTML) format. The present invention also provides two mechanisms to allow user to define t he query: either through configuration files or through a graphical user interface. It is designed in such a way that it can be easily implemented as stand-alone application, for batch processing, or interacting with other applications. The query processing module and the graphical user interface modules are written in the Java programming language and the Java Database Connectivity (JDBC) technologies. The technique of data retrieval disclosed in this invention is different fro m existing techniques in its high degree of flexibility and complexity in terms of the query structure, y et efficient processing and accurate output result. Because the output is also in tree structure, it eliminates data redundancy and more readable. Furthermore, it is designed as generic as possible and can be used for any data retrieval as long as a tree structure can be defined among the tables or nodes. It can be used in a wide range of systems for database publishing, content management, supply chain management (CRM), electronic data interchange (EDI), and other e-business applications and middleware.
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