Abstract: In order to overcome the shortcoming of current ORM component in which the data type can not be changed dynamically, a dynamic O/R mapping framework, DORM, is constructed. This framework consists of an object model, UDO, and a query language, UQL. The dynamic O/R mapping framework not only provides the storing and processing of data types, objects and the relationship of inheritance and composition between the two types, but also implements the dynamically updating of types. Both the implementation and application of DORM are presented in this paper.