Engineering application domains need database management systems to supply them with a good means of modeling, a high data access efficiency and a language interface with strong functionality. This paper presents a semantic hypergraph model based on relations, in order to express many-to-many relations among objects belonging to defferent semanic classes in engineering applications. A management mechanism expressed by the model and the basic data of engineering databases are managed in main memory. Especially, different objects are linked by different kinds of semantics defined by users, therefore the table swap, the record swap and some unnecessary examinations are reduced and the access efficiency of the engineering data is increased.C language interface that includes some generic and special functionality is proposed for closer connection with application programs.
