TREE STRUCTURE ER GRAPH GENERATOR

PROBLEM TO BE SOLVED: To enable the direct designation of an entity type to be actually contained in a tree structure, the generation of the tree structure for which the related information except cadinalities is utilized and the easy extension of a recursive structure. SOLUTION: An ER graph(entity related graph) generation means 1 displays an original ER graph. A selection means 2 selects the entity type to be finally contained in a tree structure ER graph from among the displayed entity types. A tree structure ER graph generation means 4 notices the parentage and the cardinality between the selected entity types, determines a route entity type and automatically generates a tree structure ER graph by tracing the relation of N:1 from the route. The generated tree structure ER graph is displayed by a tree structure ER graph edition means 5. A user is not required to be conscious of the route of the tree structure.