This paper introduces WHYMX object-oriented data base system suitablefor a certain of domains such as CIMS, CAD, Al and GIS. WHYMX gives the theoreticaldescription of aggregation and generalization standardization, presents the concurrencecontrol strategy, the storage management strategy and the object management mechanismof complex objects. WHYMX supports nested transaction and management of large storage object. WHYMX adds the operations of tuple--based and value--oriented in the objectdescription. Therefore, it has many advantages of the object--oriented data model and therelation data model.