Multiple Class Objects

The object-oriented database model is not standardized till this time. Very important theme is the multiple inheritance. But using of the persistent objects playing more roles during their lifetime time extends this topics toward the multiple class objects. It is difficult to define the semantics of the multiple class object especially in the part of virtual methods. For the standard multiple inheritance it is defined, which of the virtual method implementation is actual in every time and the implementation conflicts can be checked during the compile time. For the multiple class objects the rules for the definition of actual implementation are not defined. Moreover, the necessary checking leads to the time consuming run time algorithms. This paper tries to define rules for the multiple class objects, which make it easier to select an actual implementation of virtual methods and make possible checking during the changing of the object types.