数据库系统三级模式结构的不足与改进

The Insufficient and Advance of Three Classes Mode Structure for Database System

分析了数据库系统的三级模式和二级映像的不足,提出了数据库系统的四级模式体系结构.四级模式体系结构以元数据为系统设计基础,使用四级映像技术,使得数据库系统具有更为完善的应用性能.

The paper analyses the shortcoming for database system with using three classes mode and two classes image technology, and presents the mode structure of four classes for database system. Because the database system is based on the metadata for designed system and is used four classes image technology, so it possesses the perfect performance.