1. A graphic database system comprising: external storage means for storing therein a graphic object file in which graphic data expressed as an object in terms of a predetermined description based on an object oriented language is registered; mapping means for mapping a memory space of the graphic object file stored in the external storage means on a memory space of a virtual memory area which is accessed by a logical address; real memory means having a memory space and which is accessed by a real address; memory management means for said memory space matching said memory space of the real memory means, corresponding to the memory space mapped by the mapping means and the memory space of the graphic object file stored in the external storage means; and processing means for accessing the memory space of the real memory means which has been matched by the memory management means in correspondence with an access to the memory space of the virtual memory area which has been mapped by the mapping means to thereby execute processing, selected from the group consisting of registration, retrieval, updating and deletion of the graphic data in the external storage means.