自己顶一下， to: dd_zhouqian 下面是多层结构的好处， 至于是三层还是更多层， 就看需要了， 详情请参见 c++buidler 帮助文件 multi-tiered applicationsThe multi-tiered database model breaks a database application into logical pieces. The client application can focus on data display and user interactions. Ideally, it knows nothing about how the data is stored or maintained. The application server (middle tier) coordinates and processes requests and updates from multiple clients. It handles all the details of defining datasets and interacting with the remote database server. The advantages of this multi-tiered model include the following:Encapsulation of business logic in a shared middle tier. Different client applications all access the same middle tier. This allows you to avoid the redundancy (and maintenance cost) of duplicating your business rules for each separate client application. Thin client applications. Your client applications can be written to make a small footprint by delegating more of the processing to middle tiers. Not only are client applications smaller, but they are easier to deploy because they don抰 need to worry about installing, configuring, and maintaining the database connectivity software (such as the Borland Database Engine). Thin client applications can be distributed over the Internet for additional flexibility.Distributed data processing. Distributing the work of an application over several machines can improve performance because of load balancing, and allow redundant systems to take over when a server goes down. Increased opportunity for security. You can isolate sensitive functionality into tiers that have different access restrictions. This provides flexible and configurable levels of security. Middle tiers can limit the entry points to sensitive material, allowing you to control access more easily. If you are using HTTP or MTS, you can take advantage of the security models they support.
你到Delphi 5开发人员指南（李维）
里面有个例子，具体的忘记了
可以用的是DCOM或者SocketConnection
如果还不明白
可以联系我
我这里有一些小例子
Delphi 5.x 分布式多层应用系统篇-李维写的,很好!
看后你一定会写了!
www.delphibox.com有下.
你们有几个实例，都是很简单的，哪个，
也就是原理型的吧。
http://www.delphifans.com
to: dd_zhouqian
下面是多层结构的好处， 至于是三层还是更多层， 就看需要了，
详情请参见 c++buidler 帮助文件 multi-tiered applicationsThe multi-tiered database model breaks a database application into logical pieces. The client application can focus on data display and user interactions. Ideally, it knows nothing about how the data is stored or maintained. The application server (middle tier) coordinates and processes requests and updates from multiple clients. It handles all the details of defining datasets and interacting with the remote database server.
The advantages of this multi-tiered model include the following:Encapsulation of business logic in a shared middle tier. Different client applications all access the same middle tier. This allows you to avoid the redundancy (and maintenance cost) of duplicating your business rules for each separate client application.
Thin client applications. Your client applications can be written to make a small footprint by delegating more of the processing to middle tiers. Not only are client applications smaller, but they are easier to deploy because they don抰 need to worry about installing, configuring, and maintaining the database connectivity software (such as the Borland Database Engine). Thin client applications can be distributed over the Internet for additional flexibility.Distributed data processing. Distributing the work of an application over several machines can improve performance because of load balancing, and allow redundant systems to take over when a server goes down.
Increased opportunity for security. You can isolate sensitive functionality into tiers that have different access restrictions. This provides flexible and configurable levels of security. Middle tiers can limit the entry points to sensitive material, allowing you to control access more easily. If you are using HTTP or MTS, you can take advantage of the security models they support.