Research On Transforming PIM To Hbase Target Model Based On MDA

With the increasing complexity and scale of software, some problems such as low software productivity, poor portability, low interoperability and difficulty in maintain documents stand out more and more clearly. Under such a background, OMG (Object Management Group) proposed a new software development methodology——MDA (Model Driven Architecture) in 2001. MDA would help to reduce the coupling between business logic and specific implementation technology of the system, reduce the impact of demand changes to the software development effectively, and enhance the development productivity, portability, interoperability and maintainability of the system. In addition, with the coming of the big data era, HBase as a non-relational database becomes widely used and it is very suitable for big data processing. Due to the superiority of HBase, a growing number of web applications begin to try to build a data center based on it. Research questions such as migration between traditional database and HBase, designing the data model of HBase become very valuable.In this paper, the method of model transformation from Class Diagram model (Platform Independent Model, PIM) to HBase (Platform Specific Model, PSM) data model was discussed based on MDA. This method gave the idea of automatic transformation in metamodel level. At first, this paper gave the metamodels of Class Diagram model and HBase data model based on Ecore. Then transforming rules from source model to target model were designed. At this time, the ATL (Atlas Transformation Language), a model transforming language, was used to describe the transforming rules. At last, an instance which conforms to the Class Diagram model was gave to verify the automatic transformation from Class Diagram model to HBase data model. This paper aimed to explain the feasibility of automatic generation of target database schema. The method we proposed is also an inspirational case for automatic generation of NoSQL database schema.In order to generte efficient and correct codes, the completeness and correctness of PSM such as HBase model must be guaranteed, so model validation is indispensable. Because of that, this paper designd a model validation tool which invoked the XML parser to read the target model and the metamodel elements to generate a target model tree and a metamodel tree. Finally, traversaled the target model and compared its metamodel tree to verify whether or not the generated PSM conforms to the definition of its metamodel. This method was used to ensure the accuracy of model transformation.