Abstract: Because a user can define new data types in extensible DBMS,DBMS's built in index mechanism can not support quick access for special requirement. Therefore,the new access method extended by the user is one of the basic functions of extensible DBMS. The principle, method, and implementation strategies of the new index structure extended by the user in extensible database management system, NHEDB are introduced. An implementation scheme based on data dictionary and function library is proposed. The data dictionary is used for the interface between DBMS and extended module. The function library,which includes 14 functions,is the interface between the user and extended module. Various effects on DBMS,the design of extensible interface,and implementation algorithms are also discussed.

Key words: database management systems, indexes-mechanism, sections