CHAPTER  21

Developing Applications for the Internet and the World Wide Web

This chapter shows you how to use Microsoft Access to develop applications that retrieve, publish, and share information on the Internet or a local area network (LAN). For example, you can create applications that display HTML documents in forms, or you can publish or share information from a database located on a Web server. You can also create hyperlinks that you click to navigate to database objects and other Microsoft Office documents located on a local hard disk or a local area network.

What Is the Internet?

In all likelihood, you are well aware of what the Internet is, and you've had a chance to take advantage of its many resources. Even if you have used the Internet, the following overview will help to make sure you understand the terms used to describe it in this chapter.

The Internet is a collection of computer networks that connects millions of computers around the world. The World Wide Web is a client/server technology used to access a vast variety of digital information from the Internet. Using a software client called a Web browser, such as Microsoft Internet Explorer, and a modem or other connection to an Internet Service Provider (ISP), you can easily access text, graphics, sound, and other digital information from practically any computer in the world that is running the appropriate server software on the Internet.

Your Web browser uses a variety of standardized methods for addressing and communicating with Internet servers. These methods are called protocols. The most common protocol is Hypertext Transfer Protocol (HTTP), which was originally created to publish and view linked text documents, but has been extended to display and run a growing variety of graphics, sound, video, and other multimedia content. Other common protocols include File Transfer Protocol (FTP), Gopher, telnet, RealAudio™, as well as protocols used to start other applications such as e-mail and Usenet newsreaders.

To run or display Internet content with a Web browser, you type an address called a Uniform Resource Locator (URL) into its address box. For example, this is the URL for the What's New page on the Microsoft Access Developer Forum Web site:

http://www.microsoft.com/accessdev/whatsnew.htm

A URL specifies the location of a file on an Internet server. Your Web browser uses a URL to download and open the file, which is most typically a page formatted with Hypertext Markup Language (HTML) tags. HTML tags are codes enclosed in angle brackets that are used by a Web browser to determine the structure and appearance of an HTML document, such as graphic elements and text formatting. For example, the two HTML tags in the following sentence:

Make <B>this text</B> look bold.

Cause the text to display like this when viewed with a Web browser:

Make this text look bold.

To navigate to other pages or multimedia content, a user clicks a hyperlink on a Web page. A hyperlink is colored and underlined text, or a graphic, that activates a URL to download and open another file, such as another Web page or some form of multimedia content, such as a picture or sound file.

You can use HTML tags called anchors to create hyperlinks. An anchor with an HREF attribute jumps to a file outside of the current document. For example, the following anchor creates a hyperlink that jumps to the Microsoft home page:

<A HREF="http://www.microsoft.com">Microsoft Home Page</A>

An anchor with a NAME attribute creates a bookmark at a location within the same document. Other hyperlinks can jump to the bookmark created with this type of anchor.

HTML was originally a simple system for publishing documents on the Web, but it's rapidly evolving to include features that you can use to create sophisticated, interactive applications.

Tip   You can view an HTML reference that describes the most commonly used HTML tags as well as recent additions supported by Microsoft Internet Explorer and Netscape™ Navigator at http://www.microsoft.com/workshop/author/newhtml/.

If you install Internet server software on servers connected by a local area network (LAN), you can use these same Internet technologies to share data within an organization. Such a system is called an intranet or internal Web. For example, your organization could post human resources information for all employees on a Web page, or a project team could post information about its members and provide hyperlinks to important documentation about the project. All the features in Microsoft Access and Microsoft Office that are designed for the Internet can also be used on an intranet.

Microsoft Office and Microsoft Access Internet Features

In all Microsoft Office 97 applications except Outlook™, you can create hyperlinks in documents or files to display and run standard Internet content. These Microsoft Office applications also extend hyperlink technology so that you can create hyperlinks to navigate between Microsoft Word documents, Microsoft Excel worksheets, Microsoft PowerPoint slides, and Microsoft Access database objects that are stored on a local hard disk or on a LAN. You don't need Internet connections or servers to use hyperlinks to navigate between Microsoft Office documents or files. You can use both kinds of hyperlinks in the same application.

Microsoft Access provides many ways to create applications that display and run content that is available on the Internet or an intranet. For example, you can use Microsoft Access to publish information from datasheets and reports as Web pages. You can also use Microsoft Access to create files that query a database on a Web server, and then return a Web page to display the results of the query. In addition, you can save a Microsoft Access form as a Web page that emulates many of the features of the form so that users can view, enter, and update information in your database.

The following table summarizes the features available in Microsoft Access that you can use to work with content on the Internet or an intranet.

The following sections describe each of these features in more detail.

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