【摘要】 用户访问控制是数据库应用系统需要解决的一个关键问题。该文提出了一个设计模式OPACD,它将用户数据抽象成对象中间件,并在此基础上将系统的控制功能分而治之,在解决复杂的数据库访问控制问题的同时,保证了系统的扩展性、适应性和可维护性。文章还描述了模式协作中涉及的两个关键算法,并进行了应用。更多还原

【Abstract】 T hi s paper presents an object-oriented design pattern,named OPACD,for access con trols on databases,which is critical in database application systems.The patte rn abstracts users’ data as middles,and then divides the controls into many asp ects to solve.It not only makes the application systems more flexible and exte nsible,but also makes it easier to maintain.This paper also presents two key algorithms used in OPACD and a system,which is designed with OPACD.更多还原