The Internet and the database

Data | database Internet and database
http://tech.sina.com.cn 2000/04/14 Software Institute of the World Academy of Sciences Li Chunxiao
Times have changed and greetings have changed. Friends to meet, a sentence "Eat it?" ", don't

People must think that you have just come out of history and asked, "Internet?" "Maybe a chat will stop the car."

and "Internet", "database", I am afraid already is the computer industry and the vast number of enthusiasts relish the vocabulary, it is evident that int ernet and database development in full swing, unstoppable.

Walk into the Internet

The internet has developed so far, just as it has been a huge spider web covering our planet.

The name of the internet comes from the U.S. Department of Defense's "the internetting Proj ECT" network project, namely ARPANET. Later, NSFNet became the backbone of the internet in the late 80 as a result of a huge investment in NSF, National science Foun dation. By the 90 's, ans Company (Advanced network& Service Inc.) A new high-speed backbone network is established and ansnet with all backbone nodes of the NS Fnet, thus becoming the current Internet backbone. The internet is prairie Fire and global.

When we use one of the Internet, we are already facing the whole world.

So what does the Internet do?

Services on the Internet

Internet services, tens of thousands, can be summed up broadly into three categories: basic services, information services, and news bulletin services, as shown in table 1.

All kinds of services in the Internet, the fastest development, the most popular when the number of WWW (World Wide Web). The technology it uses is mainly Hypertext Markup Language HTML (Hyper Text Markup Language) and the global Resource Locator U-RL (Universal Resource Locator), and the wonderful thing is that you can "roam" around the world with just a little bit of your mouse in hand The roaming process coincides with the divergent thinking of the human brain.

WWW call database

The most basic transmission unit on WWW is the page, and a pre-designed page (static page) is always stored in the WWW server's file system.

At first, WWW only supported simpler documents, with the continuous improvement of application requirements and the development of technology, it can not only support text, graphics, images, sound and other multimedia information, but also can support some more complex objects, such as spreadsheet objects. The essence of a Web page is a special body called a "HYPERLINK" in which users use browsers to read pages from the WWW server, and hyperlinks enable users to transfer freely between different pages, the so-called "roaming".

A WWW information provider can take pains to write a page and store it in the WWW server for a while with less information and change. Once the amount of data is large to a certain extent, it is obvious that only static pages are stretched. Let the page move up the idea of this came into being, then had to please the database, in the "dynamic page" play the leading role.

The debut of the database not only solves the dynamic, but also lets those who have real-time, interactive requirements of the user satisfaction.

Into the database

The term "database" has emerged as a veteran in the 50, relative to the Internet. In order to manage the complex and huge data, people studied various organization, use the method of data, thus have a variety of database structure model, summed up, nothing more than hierarchical, network type, relational and object-oriented type. But the four brothers, or the relationship between the boss, the most applied. It seems that a good relationship is not a person's patent.

Larger databases, such as Oracle, IBM, Informix, and Sybase, can effectively organize and manage large quantities of data, and make quick queries. This is the foundation of web database applications.

The combination of Web and database

It has become a new technology to combine web with database and develop dynamic Web database application. To understand the location of the database, through static and dynamic page processing on the comparison is self-evident.

In addition to the Common Gateway Interface (CGI), you can use an Application programming interface (API) to interact with the database. CGI provides a simple way to connect to a database, but its limitations are obvious, and restarting the CGI program for each request affects both speed and resources, resulting in slower performance and increased latency. Compared with CGI, API applications are more tightly integrated with Web servers, have much less resources to occupy the system, and are greatly more efficient in running. However, APIs are not all good because developing API applications is much more complex than developing CGI applications, and the compatibility between various APIs is poor.

In addition to using the above method on the Web server side, the application can be downloaded to the client through a Web browser, and the database is accessed directly from the client. Client applications include: Java applets, ActiveX, plug-in, and so on, most typically Java App let.

Accessing a database In a Java applet enables you to use JDBC (Java Database connectiv ity) technology to implement various operations on different databases that are distributed across the web using JDBC-provided APIs, and to give access to a database to a dedicated server. The Java applet passes the request and result of the database operation through the socket communication with the dedicated server.

Popular Web Database Products

1.Microsoft

Microsoft's Web server product is Internet Information Server (IIS), which provides an ISAPI (Intranet server API) as a programming interface to extend Web server functionality; It also provides an Internet Database Connector (IDC) that enables querying and updating of databases. Another Microsoft product is Mi crosoft Visual InterDev, which also presents an ASP (Active Server Pages) as a solution for implementing dynamic Web applications. Microsoft Visual InterDev is a Web application rapid development environment that provides server and client-side programming tools, database Tools, and content-editing tools, as well as integrated site management capabilities.

2.Netscape

To improve performance, Netscape introduced the Application programming interface NSAPI (Netscape Server API) to its Web server. With NSAPI, developers can extend the functionality of the server, including access to external databases. NSAPI can support platforms such as Windows NT, Solaris, and Hp/ux, but there is currently a lack of better development tools for direct NSAPI programming.

3.Oracle

Oracle webserver is more than just a Web server product, with its efficient, multi-threaded, scalable architecture, O racle webserver can effectively integrate with Oracle databases and provide the appropriate development environment, and thus is the tool for developing Web database applications.

4.Informix

Unlike other web solutions, Iuwa manages all Web applications intelligently in the Informix database, including HT ML documents, application templates, and various multimedia content. Mainly have IUWC, iuserver, data blades and other tools and services.

5.Borland

Borland has always been a leader in development tools, particularly in terms of its Open Database connectivity technology based on DBE (Borland Databa En gine) and Delphi's Visual Rapid Application development (RAD) tools. Delphi's client/server version is not only an efficient client/Server Rapid Application development tool, but also a new technology for Web applications.

6.Sybase

Sybase proposes a middleware web.sql that connects Web servers to Sybase database servers and runs on platforms such as Win dows NT, SUN Solaris, and supports CGI and NSAPI two interfaces. Sybase's PB (Power Builder) has also increased the number of Internet support since 5.0, enabling developers to quickly build, Dynamic Web server applications.

In short, the above products and technologies have their own characteristics, but there is no one can be compatible with different operating systems, Web servers and database systems, and has a good development and operational efficiency. Therefore, various factors should be considered when designing the system.

Table 1

Service category Service Name brief

Basic Class E-mail (e_mail) enables fast, inexpensive communication between Internet users over the network.

Basic class remote Login (telnet) Internet users telnet to the in Ternet host using the emulation terminal.

Basic class File Transfer Service (FTP) Internet users transfer files between computers via the FTP protocol.

Information class Gopher means "go for", through the Gopher protocol, the use of Multi-level menu interface for Internet users to provide information query function.

Information class WAIS provides Internet users with the ability to automatically query various databases distributed online.

Information class WWW (World Wide Web) based on hypertext information Query tools, can achieve a global range of information retrieval.

news bulletin Class Network News (Usenet) utilizes the Internet for discussion in international forums.

News bulletin Class Bulletin Board (BBS) post information.