A method executed by a computer system for converting a database schema in relational form to a schema in object-oriented (00) form. The input is the schema of a database in relational form including all relations of the schema and the primary keys, reference keys, and attributes of each relation....http://www.google.com.hk/patents/US5797137?utm_source=gb-gplus-share專利 US5797137 - Method for converting a database schema in relational form to a schema in object-oriented form 
