论文题目：关于数据库系统设计中面向对象技术的应用
第一部分 外文翻译
Application of object-oriented database system
design technology
Abstract: The basic idea of object-oriented technology and development process, describes the implementation of object-oriented technology. A detailed discussion with concrete examples in the database system architecture design and detailed design of object-oriented technology, the use of surface to the object database system analysis and design methods, the use of the UML tool to establish a specific object model, gives a more general-purpose database system development model systems designed to use the mode reuse, and easy to maintain, in order to effectively improve the quality of the development of database systems.
Keywords: Object-Oriented Database System Designed Object Model An Object-Oriented Basic Concepts Of
1.1 Object (Object) Method (Method) And Message (Message)
Objective world is constituted by the entities in the objective world and their mutual relationship between the objective world of abstract entities for objects in the problem space we need to solve different problems, we face the object is different, so the object is not fixed. A book can be an object, a library can also be an object. Dynamic point of view, the object and its operation is the behavior of the object, an object is usually defined as: the object is operating on a set of information and its above description.
Private data structure and processing, these processes also known as operations (Operation) or method (Method), including control and process private data, said
the state of the object, the state only by a private operation to change, whenever the need to change the object the state, you can only send messages to the object by other objects.
Message is used to request the object to perform an operation or to answer certain requests for information, the message unified data flow and control flow, program execution is against the objects pass the message that the message in the form of news mode. different messages of the same message mode, the interpretation and processing by the same object are the same, but operating results due to the different state of the object. a message of a schema defines object, all messages mode and message mode processing capabilities, define the external characteristics of the object.
1.2 (Class), Instance (Instance), Inheritance (Inheritance)
In the objective world, there are many things that have the same characteristics, such as: cars, buses, trucks, etc., can be classified as a motor vehicle. From the object point of view, common property, common operational nature a collection of objects is class, and a single object is an instance of the corresponding class. For example: the book is a class, a specific book, such as << >> of object-oriented analysis is an instance of the class, any object is instance of a class, and inherit the class definition of private data and operations. This is the inheritance of a class is essentially defined an object type.
Constitute a class hierarchy, the relative upper superclass, the relatively lower subclass, subclass inherit the super class's private data structure and operation at the same time can have its own private data structures and operations. If a
subclass has only one super class is called single inheritance, then the class shared superclass attributes and operations.
Class and inheritance are important concepts in modern software engineering, software reusability, reusability of program components of the inherited class attributes and operations in many industrial observation believe that reusable software is not to create a tradition over the program (subroutine library), but achieved through the establishment of a \
1.3 Package (Encapsulation)
The Encapsulation Of The Object Is Reflected In The Following Areas: Object with clear boundaries: the scope of the object's internal software (data structures and operations), limited to within the boundaries of objects with a unified external interface: the interface of the object (message mode) to describe the interaction between the object and other objects are not open to the internal implementation of the object: the object's implementation gives the details of the object provides the functionality of external objects can not access this feature details.
Information hiding is an important concept to emphasize in the software development process, the encapsulation of the object reflects this concept. This convenient starting a object-oriented technology developed by the design of software maintainability greatly improved software technology to the pursuit of one of the goals.
Surface To The Object In The Database Design Process
Object-oriented technology is an important application in the database system is object-oriented database system, with the expansion of the database applications, new application areas, such as computer-aided design, computer-aided software engineering, hypertext applications proposed simulation of complex objects, the new demands of the complex behavior of the simulated object. a traditional relational database is difficult to meet these requirements, application development to promote the study of the database of new technologies, object-oriented database systems have emerged.
Object-oriented technology in the database system is another important application of object-oriented database application development tool. With the development of client / server architecture, as well as the needs of enterprise-wide database applications the traditional relationship database application developers to put forward new requirements on database application development tool, to support the development of graphical user interface (GUI) and reuse of software components, the development team's work, the scalability of the application system, and scalability. echoes with these requirements, database vendors and tools developers of object-oriented technology to the relational database application development tool, the introduction of object-oriented database application development tool, and put into the market, in a relational database application development using object-oriented technology provides a strong support.
Database management system development process including requirements analysis and system design in two phases, after the completion of a needs analysis,
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