Shulou(Shulou.com)06/03 Report--

This article mainly introduces the use of Ajax core XMLHTTP components, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let Xiaobian take you to understand.

1. Database remote management technology

An important link in the modern application of wide area network based on Internet is the remote monitoring of database. First of all, let's briefly review the development process and mode of database remote management technology on the Internet: (recommended article: AJAX topic)

In the early stage, the database was managed remotely by writing CGI-BIN program module. However, the running speed of CGI-BIN is slow and the maintenance is very inconvenient, so it has been basically abandoned now.

In recent years, there are many applications using component object model (Component Object Model, COM), and the effect is very good. However, if you are using a third-party server (the author's website is based on a third-party virtual host), the server often does not allow users to register their own components for confidentiality or other commercial reasons.

In recent years, the. Net platform launched by Microsoft and the J2EE platform of SUN are very high-end database remote management and service platforms. Can provide high-quality multi-layer (n-Tier) application services. Net's simple object access Protocol (Simple Object Access Protocol, SOAP) using Hypertext transfer Protocol (Hypertext Transfer Protocol, HTTP) and Extensible markup language (Extensible Markup Language, XML) technology to achieve cross-system (such as Windows-Linux) communication services has been widely accepted and used by developers. Many large-scale applications, such as enterprise resource planning (Enterprise resource planning, ERP), are built on such a large platform. However, for small and medium-sized applications, such as the construction and maintenance of a website, this kind of large-scale application platform seems to be too big and too expensive.

Microsoft, which once lagged behind in Internet technology and Java technology, took the lead in XML application development. The XMLHTTP protocol in her XML parser (MSXML) is a very convenient and practical client / service communication channel. With the comprehensive use of XMLHTTP and ActiveX data objects (ActiveX Data Objects, ADO/ADOX), the remote management of database can be realized easily.

II. Database remote management system

The task flow of remote database management is:

1. The client sends instructions to the server to query or modify the database structure and data.

2. The server accepts and executes the relevant instructions and returns the results to the client.

3. The client accepts and displays the execution result of the instruction returned by the server.

The two key links to realize the remote management of database are:

1. The data channel for uploading instructions and downloading results between client and server is implemented by XMLHTTP protocol.

2. The instruction transmission and result return between the server front and the database are completed by the ADO/ADOX interface which plays the role of the middle layer.

III. The use of XMLHTTP

As the name implies, XMLHTTP is a hypertext transfer protocol that transmits data in XML format.

In fact, XMLHTTP's data transfer process is a little more flexible:

The instructions it uploads can be data in XML format, strings, streams, or an array of unsigned integers. It can also be a parameter to URL.

The result can be in XML format, a string, a stream, or an array of unsigned integers.

Please refer to the link at the end of the article for details.

The process for the client to call XMLHTTP is simple, with only five steps:

1. Create a XMLHTTP object

2. Open the connection with the server, and define the instruction sending method, service web page (URL) and request permission, etc.

The client opens a connection to the service web page of the server through the Open command. As with normal HTTP instruction delivery, you can use the "GET" method or the "POST" method to point to the service web page on the server side.

3. Send instructions.

4. Wait for and receive the processing result returned by the server.

5. Release the XMLHTTP object

Thank you for reading this article carefully. I hope the article "what is the use of Ajax Core XMLHTTP components" shared by the editor will be helpful to you. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.