Mapping Technique of STEP Data Model in Relational Database Based on Data Storage

STEP is the most effective way to describe product data model. But object-oriented database in the implementation of STEP schema can not be directly integrated with the manufacturing information management system based on relational database system. So it needs to transform the product data model to relational data model. This paper deals with the mapping technique for different data types in STEP. First a data dictionary needs to be established, which is used to look up the definition of entity and relations of the operation data and to make the corresponding data manipulation language (DML) statements execute. Then the mapping rule of EXPRESS data style to relational database, including basic data type, object data type and inheritance, is described. Finally an entity instance manager based on data storage is provided to realize the persistency of STEP data in relational database. The mapping technique discussed in this paper can be used in all STEP data schemas.