9 IIS和WEB应用程序的具体细节
IIS（Internet Information Services）是Windows操作系统的组成部分之一，它服务与对Web站点的请求。IIS管理器用树形结构显示Web站点的集群，每个站点都被设置成通过IP地址，端口，和一个主机头接受请求。其中主机头使得一个IP地址，根据不同的域名，能访问多个站点。当一个HTTP请求达到服务器是，IIS根据请求的文件的扩展名判断由哪个应用程序来处理请求，如果没有找到匹配的扩展名，被请求的文件将不经过任何处理直接发送给客户端。
IIS首先获取请求并判断由哪一个ISAPI（网络服务应用程序接口）程序来处理。以ASP.NET为例，它将请求交由aspnet_isapi.dll处理。
ASP.NET把以多个不同物理文件形式存在的页面编译成一个程序集并缓存起来供其他请求使用。在多种可能的编码模型中，inline编码和code-beside是最简单也是最实用的代码编写及维护形式。
由发布程序执行的预编译可以通过隐藏代码、预先检查错误和防止在第一次请求是执行编译等方式来缓解部署应用程序的压力。
10 测试、测试、再测试
以我个人的观点来看，测试在了解需求阶段就已经考试了。任何开发人员在Visual Studio里面敲入“Public Class”之前，就必须对你的软件所要实现的功能有一个非常清晰的认识，这就要求每一个项目相关人员（最终用户、业务专家、数据库管理员、硬件人员等）都必须介入到软件的开发过程中，这些人员必须参与开发的整个过程。把开发看成一个渐进的过程要比你在项目一开始的时候就确定你将要交付给客户的一个什么样的产品容易得多。
如果使用测试驱动的开发方法，在实际编码前应先写好相应的测试代码。一般来说，这些测试的代码应该尽量以能够让需求分析员（也许就是你自己）能读懂这些代码并测试这些代码实都能够满足预期的使用目的。
测试是伴随整个开发过程的，如果一个或多个测试失败，您将不得不修改自己的代码来确保测试顺利通过，而绝不是等写完了所有代码之后才去测试。
所有代码接近完工的时候，你的传统测试就可以开始了，这个时候你可以让测试人员去检查那些用户接口部分还有哪些不合理的地方（可以使用类似ACT的自动化工具）。因为在整个开发过程中，你一直在测试，所以这个时候系统底层的业务逻辑应该已经可以很好的工作。
从项目的理想到软件的最终发布，你的项目的所有相关人员都必须参与到开
发的整个过程中一确保你的软件能够满足预期的使用需求。
十一 访问关系数据库
所有数据库应用都有以下结构：
.数据库客户 .数据库服务器 .数据库
数据库客户是为系统提供界面的用户应用。通常这是一个GUI应用，允许用户查询和更新数据库。
SQL
SQL是指结构化查询语言（Structured Query Language）。只是数据库客户与实现了这个标准的不同厂商的数据库系统哦你之间进行通信所采用的一种标准方法。
数据库客户要通过SQL语句与数据库服务器进行通信。图12-5显示了数据库客户/服务器模型的一般解决方案。
SQL 用户 数据库 客户 数据库 服务器 数据库 驱动程序
附件2：外文原文 1 Designing with Objects
Generally, a solid OO design process will generally include the following steps: 1. Doing the proper analysis
2. Developing a statement of work that describes the system 3. Gathering the requirements from this statement of work 4. Developing a prototype for the user interface 5. Identifying the classes
6. Determining the responsibilities of each class
7. Determining how the various classes interact with each other 8. Creating a high-level model that describes the system to be built
The system, or object model, is made up of class diagrams and class interactions.This model should represent the system faithfully and be easy to understand and modify.
2 What Exactly Is a Class?
In short, a class is a blueprint for an object.When you instantiate an object, you use a class as the basis for how the object is built. In fact, trying to explain classes and objects is really a chicken-and-egg dilemma. It is difficult to describe a class without using the term object and visa versa. For example, a specific individual bike is an object. However, someone had to have created the blueprints (that is, the class) to build the bike. In OO software, unlike the chicken-and-egg dilemma,we do know what comes first—the class.An object cannot be instantiated without a class.
To explain classes and methods, it’s helpful to use an example from the relational database world. In a database table, the definition of the table itself (fields, description, and data types used) would be a class (metadata), and the objects would be the rows of the table (data).
3 Prototyping the User Interface
As our final step in the OO design process,we must create a prototype of our user interface.This prototype will provide invaluable information to help navigate through the iterations of the design process.As Gilbert and McCarty in Object-Oriented Design in Java aptly point out,“to a system user, the user interface is the system.”There are several ways to create a user interface prototype.You can sketch the user interface by simply drawing it on paper or a whiteboard.You can use a special prototyping tool or even a language environment like Visual Basic, which is often used for rapid prototyping. Or you can use the IDE from your favorite development tool to create the prototype.
However you develop the user interface prototype, make sure that the users have the final say on the look and feel.
4 Inheritance
One of the most powerful features of OO programming is, perhaps, code reuse. Structured design provides code reuse to a certain extent—you can write a procedure and then use it as many times as you want. However, OO design goes an important step further, allowing you to define relationships between classes that facilitate not only code reuse, but also better overall design, by organizing classes and factoring in commonalties of various classes. Inheritance is a primary means of providing this functionality. Inheritance allows a class to inherit the attributes and methods of another class.This allows creation of brand new classes by abstracting out common attributes and behaviors.
One of the major design issues in OO programming is to factor out commonality of the various classes.
5 Using Object Persistence
Object persistence is another issue that must be addressed in many OO systems. Persistence is the concept of maintaining the state of an object.When you run a program, if you don’t save the object in some manner, the object simply dies, never to
be recovered.These transient objects might work in some applications, but in most business systems, the state of the object must be saved for later use.
In its simplest form, an object can persist by being serialized and written to a flat file.The state-of-the-art technology is now XML-based.Although it is true that an object theoretically can persist in memory as long as it is not destroyed,we will concentrate on storing persistent objects on some sort of storage device.There are three primary storage devices to consider:
. Flat file system—You can store an object in a flat file by serializing the object.This has very limited use.
. Relational database—Some sort of middleware is necessary to convert an object to a relational model.
.OO database—This is the logical way to make objects persistent, but most companies have all their data in legacy systems and are just starting to explore object databases. Even brand-new OO applications must usually interface with legacy data.
6 What Is UML?
UML, as its name implies, is a modeling language.The UML User Guide defines UML as “a graphical language for visualizing, specifying, constructing and documenting the artifacts of a software-intensive system.”UML gives you a standard way to write the system’s blueprints. In a nutshell,UML offers a way to graphically represent and manipulate an object-oriented (OO) software system. It is not only the representation of the design of a system, but a tool to assist in this design.
7 ASP.NET Overview
ASP.NET is a unified Web development model that includes the services necessary for you to build enterprise-class Web applications with a minimum of coding. ASP.NET is part of the .NET Framework, and when coding ASP.NET applications you have access to classes in the .NET Framework. You can code your applications in any language compatible with the common language runtime (CLR), including Microsoft Visual Basic, C#, JScript .NET, and J#. These languages enable you to develop ASP.NET applications that benefit from the common language runtime, type safety, inheritance, and so on.