With the continuous development of network technology, a variety of network applications explosion. The architecture is based on the use of most browsers + server B / S structure, the other is a C / S structure-based.
Overview:
BS = Browser / Server = + server browser
example: the major sites, such as CSDN
C / S = Client / Server = + client server
example: QQ, Thunder, Nora, LOL
B / S structure:
In this architecture, the client does not need to develop any interface, unified use Chrome and Firefox browser, sends a request to a Web server through a Web browser, have a Web server for processing, and the results processed gradual transfer back to the browser. This structure continues to mature and take advantage of the popularity of the browser base to achieve the original complex software is a powerful realization, thereby saving development costs.
advantage
- Low TCO
- Easy maintenance
B / S structure of the management server software only on the line, all clients only browser, does not need to do any maintenance. No matter how large the user, how many branches will not increase the workload of any maintenance upgrades, all operations need only for the server; if it is off-site, server just need to connect to a private network, remote maintenance, upgrades and share - Strong distribution
- To develop a simple
- You can not install any special software to operate can be achieved anywhere
- Zero client maintenance
B / S structure of the product clearly embodies the more convenient features. For a slightly larger units, system administrators If you need to run back and forth between a few hundred or even thousands of computers, efficiency and workload can be imagined, but the B / S structure of the management server software only on the line , all the client only browser, does not need to do any maintenance. - Expansion of the system is very easy
- As long as there is an operating system and browser you can use
Shortcoming
- Large communication overhead, system security and data protection more difficult.
- High performance requirements of the server:
As the B / S architecture management software is only installed on the server (Server), network managers need to manage servers only on the line, network managers need to do hardware maintenance. However, the application server running the data load is heavy, the issue once the server "crash" occurs, the consequences could be disastrous.
C / S structure:
On Client / Server (C / S structure) are well-known client and server structure. It is a software system architecture, which allows you to take advantage of both ends of the hardware environment, the rational allocation of tasks to the Client side and Server side to achieve reduced communication overhead system. Most application software systems are Client / Server in the form of two-tier structure, the current system is a software application to a distributed Web applications development Web and Client / Server applications can perform the same business process, different application modules shared logic component; therefore, internal and external users can access the new and existing applications can be extended by new applications of existing application logic. This is the current direction of development of application systems
In the C / S structure, the application is divided into two parts: the server portion and a client portion. Server part is multiple users to share information and functionality, perform back-office services, such as shared databases and other control operations; client-specific user part, responsible for the implementation of front office functions, in an error message, online help and other aspects of the powerful function, and can switch between a subroutine.
Development of C / S model from a two-layer structure is subjected to a three-layer structure
composed of two-layer structure of two parts: a client front end, the main user interface display to complete, accept data entry, data validity check, a request to send back-end database accept the return result, processing application logic; the back-end server, run the DBMS, providing query and manage databases.
Layer structure has some disadvantages: the main problems: the difference scalability of the system; and other systems difficult to interoperate; difficult to support a plurality of heterogeneous databases; client and server interaction DBMS frequent, large communication network; all customers machines need to install, configure database client software, this is a very complex work, and so on.
Based on the above shortcomings of the two-story structure, a three-layer structure along with the mature middleware technology and the rise. The core concept is the use of middleware application process into three distinct hierarchical representation, business logic, and data storage layer.
A three-layer structure is two-story structure has certain advantages: a good opening; reduce overall system costs, maintenance and upgrade is very convenient; good system scalability; simple systems management for heterogeneous database support, a high availability; can be tight security management
advantage
- Give full play to the client PC's processing power, a lot of work can be submitted to the server at the client after processing.
- Data application server running lightly loaded
easiest C / S architecture database application consists of two parts, i.e., the client application and the database server program. Both procedures may be referred to the foreground and background programs. The machine running the database server program, also known as application server. Once the server program is started, it waits for a response at any time request sent by the client; the client application running on the user's own computer, to the database server, the client computer may be referred to, when the data in the database needs to carry out any operation , the client will automatically search for the server program, and its request, the server program respond in accordance with predetermined rules, the results returned, the application server running the data load is light. - Data storage management functions are more transparent
in the database application, the data storage management functions are performed independently by the server and the client application, and is generally different from those (whether known or unknown) can not be the foreground application rule violation, are implemented in a server program, such as the visitor's permission, numbers can be repeated, must have customer orders to establish such rules. All this, for the end user to work on the foreground program is "transparent", they need not bother (usually not interference) behind the process, you can complete all their work. In the client-server architecture, the foreground program is not very "thin" troublesome things are handed over to servers and networks. In the C / S system, the database can not really become public, specialized warehouses, it is subject to independent specialist management.
Shortcoming
- Distribution gender differences
- High maintenance costs
the client need to install special client software. First involves installation effort, followed by any computer problems such as viruses, hardware damage, you need to install or maintain. In particular there is a problem in many cases branch or store, not work, but the problem away. Also, the system software upgrade, each client will need to reinstall its maintenance and upgrade costs are very high.
Compare
| C/S | B/S | |
|---|---|---|
| Hardware environment | Private Network | Wan |
| Safety Requirements | Strong user group information security control relatively fixed facing | For unknown users the ability to control security is relatively weak |
| Procedural framework | Pay more attention to the process system can operate at speeds less consideration | Have multiple considerations for security and access speed, is the development trend |
| Software reuse | difference | it is good |
| system maintenance | Difficult to upgrade | Overhead is small, easy to upgrade |
| solving issues | Concentration | dispersion |
| The user interface | Closely with the operating system | Cross-platform, browser-related |
| Information Flow | Interactivity low | Intensive interaction |
Part of the article refer to Baidu Encyclopedia.
