关系数据库类型系统的扩充

The Extension of the Type Subsystem of a Relational Database

讨论了关系数据库在类型和函数两个方面的扩充问题．对于类型扩充，讨论了特殊类型、抽象数据类型以及语言类型三个方向的扩充；对于函数扩充，讨论了源函数、ＳＱＬ函数和外部函数三个方面的扩充．

With new applications arising continuously, many new requirements are being made on the function and performance of the relational database, for example, those made by the engineering design field. To meet these requirements of new application fields, the type and function extension of the relational database are described. For the extension of the type subsystem, the special, abstract data and language types to be defined by the users themselves are discussed. For the extension of the function, the source function, SQL function and external function are discussed. The dynamic binding after function extension is studied.