Research On Data Modeling In Rapid Development Platform

With the popularity of MDA technology, more and more companies have developed RAD platforms based on MDA. It can generate executable source codes directly with the user models and predefined frameworks. It raises the development efficiency and improves the software quality. Then, the data model methods of such RAD platform are discussed from three different aspects.Firstly, the metadata and its function in the software development process are analyzed. Then, the method that using pattern of the metadata repository to manage metadata is proposed, and the requirements to construct such a metadata repository are explained. The metadata repository's functions include: managing the meta-model designed by user in a consistent way, providing metadata information services for subsystem of the RAD platform. The metadata repository adopts MOF and XMI specification to share metadata in various systems. As a standalone system, it can act as a webservice to query, publish and update metadata etc.Secondly, an object graph framework (OGF) integrated with SDO concept is put forward. The OGF offers a consistent and simple data access method. It uses a data access method ground on XPath and a data operation method based on command pattern. Then, the framework and its implement detail are explained. And another framework named Unified UI Framework is proposed, which aims to generate the UI automatically and describe various clients'UI in a unified way. It improves the efficiency of developer.Finally, a codes generation system was designed and implemented. It uses Jet and JMerge technology. According to UML models designed by user, the system can generate the executable codes based on OGF and UUF. Experiments prove that it can map a UML model to rational database.As above, the three parts implement a metadata repository for managing data models, two frameworks for manipulating data models and a codes generation system separately. They construct the infrastructure of a RAD platform. These systems are based on the open source components. As a result, the cost of the RAD platform was much decreased.