外文翻译-对象技术(编辑修改稿)

外文翻译-对象技术(编辑修改稿)内容摘要：

thods that are unique to that class. Each class can have one or more subclasses. Each subclass contains the methods of its higher level classes plus whatever methods are unique to the subclass. The OOP capability to pass methods to lower levels is called ―inheritance‖. A specific instance of an object contains all methods from its higher level classes plus any methods that a unique to the object. When an OOP object is sent an instruction to do something, called a message, unlike a traditional program, the message does not have to tell the OOP object exactly what to do. What to do is defined by the methods that the OOP object contains or has inherited. Object—oriented programming can bring many advantages to users. It can bring productivity gains as high as 1000 to 1500 percent instead of the 10 or 15 percent gains XII available from structured programming methods. It allows large plex systems to be built which are not economically feasible using traditional programming techniques. It allows program modifications to be made more easily. It could mean two different user interfaces within an application, one for the user who likes to type, and another for the users who just want to shout at the terminal. Objects can be viewed as reusable ponents, and once the programmer has developed a library of these ponents, he can minimize the amount of new coding required. One user envisions a mercial library of objects which could be purchased by programmers and reused for various applications. But creating a library is no simple task because the integrity of the original software design is critical. Reusability can be a mixed blessing for users, too, as a programmers has to be able to find the object he needs. But if productivity is your aim, reusability is worth the risks. The longterm productivity of systems is enhanced by objectoriented programming. Because of the modular nature of the code, programs are more malleable. This is particularly beneficial for applications that will be used for many years, during which pany needs may change and make software modifications necessary. Software reliability can be improved by objectoriented programming. Since the objects are repeatedly tested in a variety of applications, bugs are more likely to be found and corrected. Objectoriented programming also has potential benefits in parallel processing. Execution speed under object oriented methods will improve with parallel processing. Objectoriented DBMS A shift toward objectoriented DBMSs does not have to replace relational DNMS. As its name implies, it is orientation rather than a fullblown DBMS model. As such, it can blend with and build on the relational schema. Objectoriented DBMSs integrate a variety of realworld data types –such as business procedures and policies, graphics, pictures,。