A declarative manipulation mechanism for OODB and XML DB having cyclic schema

OODB and XML DB are suitable to represent complex object. Complex object is classified into two types: nonself reference object and self reference object. The former has an acyclic schema while the latter has a cyclic schema. A cyclic schema can represent dynamic data structure, such as list, tree and graph. Certain list and tree structure can also be represented by a nonself reference object. Thus, self reference object is necessary to represent recursively defined data structure. In this paper, we propose the view function which provides declarative retrieval and manipulation mechanism for self reference trees. The view function has the following advantages. (1) The view function is suitable for GUI. (2) A user can modify an arbitrary subset of the retrieved objects. (3) The modification operation is a purely declarative. (4) Completeness and soundness of the manipulation are ensured. We also define the notion of manipulation completeness and soundness and prove these properties for tree manipulation using the view function.