Patent ID: 7885968

Claim:
A data conversion method for converting a first database system having a plurality of first queries into a second database having a plurality of second queries, wherein the first query permits all of parameter, processing of addition, deletion and updating with respect to a database, and becoming a child query of the other query, and the second query comprises: a view type which prohibits the parameter, permits the processing of addition, deletion and update, and permits becoming a child query of the other query; a function type which permits the parameter, prohibits the processing of addition, deletion and update, and permits becoming a child query of the other query; and a stored-procedure type which permits the parameter, permits the processing of addition, deletion and update, and prohibits becoming a child query of the other query, a processing circuit of the computer performs the processing of reading a plurality of the first queries of the first database from of a memory of the computer; specifying a relation of parent and child of a plurality of the first queries based on a best structure of the read first query; determining a type of the second query corresponding to the first query in order from the first query of a bottom layer to the first query of a top layer in the direction from a child query to a parent query base on the relation of parent and child; and generating the second query corresponding to the first query based on the determined type in order from the first query of a bottom layer to the first query of a top layer in the direction from a child query to a parent query based on the relation of parent and child, the determining the type of the second query is performed by the circuit and comprises determining the type by using a dummy type which is used only in the process of conversion and other than the function type and the stored-procedure type, determining the second query corresponding to the first query as the dummy type when the first query is determined as the function type, the stored-procedure type of the dummy type based on the parent child relation of the nest structure, and determining the type by determining the second query to the first query as the view type when the first query concerned is not action query, does not include parameter, and the child query thereof is not existed or is the view type, the generating the second query is performed by the circuit and comprises generating the second query of the stored-procedure type including function description equivalent to the functional description of a target query and generating the second query of the function type including function description equivalent to the functional description of the target query with respect to the target query which is the first query judged in the determining type as the dummy type or the stored-procedure type.