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Oracle PowerBrowser

This chapter is about Oracle Corporation's latest Internet product, Oracle PowerBrowser. At the time of this writing PowerBrowser is a beta product and may have some functionality changes. However, the information here will give you a glimpse of Oracle Corporation's plans for this product, its basic functionality, and an idea of how to use it.

What is the World Wide Web

Before going into the details of Oracle's PowerBrowser, it is important to get an understanding of what the World Wide Web (a.k.a. the Web or WWW) is and how it came to be. First will be a short history of the Web, including the Internet, and then a description how the browser came to be. Rounding out this section will be an attempt to predict what is happening with the Web and where it will take us.

Short History of the Web

In the 1960s the United States government, through the efforts of the Advanced Research Projects Agency (ARPA), felt it would be important to link university computers and researchers to assist them in conducting basic research through the sharing of information. This project became known as the ARPAnet. Although only 107 hosts were added to the system between 1969 and 1977, the engineers in charge of the ARPAnet realized that the new communications network was going to grow into something larger than originally anticipated. On January 1, 1983, all of the ARPAnet was switched from NCP (with a possible of 256 hosts) to TCP/IP (with a possible of 4,294,967,296 hosts) and became what is now known as the Internet. The National Science Foundation (NSF) funded most of the early development of the Internet, but on April 30, 1995, the U.S. government released the Internet to commercial networks and service providers and shut down the National Science Foundation (NSF) backbone.

Before the World Wide Web, the Internet consisted mostly of electronic mail (e-mail), Usenet newsgroups, and FTP or file transfer sites. Tools were invented to help categorize what information could be found and where it was, but the Internet was not what you would call "user friendly." If you wanted to send e-mail to a close friend at another Internet site, the easiest way to get his or her e-mail address was to use the phone and call him or her directly (this may still be the case). If you needed a particular computer program or file, it was nearly impossible to find unless you knew exactly where it was.

In March, 1989, Tim Berners-Lee at the European Laboratory for Particle Physics (CERN) proposed a new set of protocols for Internet information distribution. This set of protocols became known as the World Wide Web protocols and were soon adopted by other organizations. A consortium of organizations was formed, and it became known as the W3 Consortium.

Birth of the Browsers

Soon after the WWW protocols were defined, the National Center for Supercomputing Applictions (NCSA) worked on creating an interface for them. The goal of the interface was to provide a graphical, easy-to-use application that would encourage others to develop and support the World Wide Web. One thing that greatly helped this cause was that NCSA developed its front-end (Mosaic)simultaneously on three different graphical user interfaces (GUIs): the X windowing system found on UNIX, the Macintosh user interface from Apple Computers, and the Windows interface from Microsoft. Its release in 1993 has made the WWW the most popular Internet service in use today.

Shortly after the release of Mosaic, James Clark and Marc Andreessen got together and formed Netscape Communications Corporation. Jim was one of the founders of the highly successful Silicon Graphics Incorporated, and Marc was one of the original authors of Mosaic. Together they set out to build a better browser than Mosaic. To help gain market share, they made their browser freely downloadable for people to try, thus setting the standard for other Web browsers. Today almost every browser on the market, including Oracle PowerBrowser, is freely available.

If the browsers are free, how does anyone make any money? In order to browse the WWW, you need to have servers sending information—and those are not free. In order to take advantage of all the neat features the Netscape browser has to offer, companies, individuals, and Web site providers must utilize the Netscape server. Also, Netscape has started charging a very small fee for its browser.

Another way that companies such as Microsoft are making money is through bundles. Microsoft can provide you with a free browser or server that runs on Windows NT in hopes that it will sell more copies of Windows NT.

Oracle Corporation hopes, of course, that after you have seen the power of PowerBrowser and how easily it interacts with the Oracle Relational Database Management System (RDBMS,) you will become interested in purchasing Oracle databases.

Future Vision of the Web

The World Wide Web is about sharing information but is still in its infancy. As more companies compete in the WWW-tools and -applications business, you will see many neat and interesting enhancements made. You will also see some creative applications and uses for these products. Although only time will tell what really happens, here is where the future trends in Web technology seem to be heading both on the Internet and on standalone corporate networks.

On the Internet

Going through the Los Angeles Times, it is not uncommon to see WWW addresses of the companies promoting products in advertisements. Whether you are looking for computer-related products or designer clothes, you can go to the Web to see information about the companies selling you those products and information about the products themselves. Soon, if you are happy with the products advertised, you will be able to purchase them through electronic means. This will allow you to purchase a Hong Kong tailored suit at the local Hong Kong price without having to leave Provo, Utah or wherever you may be.

In addition to electronic commerce, you will be able to perform routine errands without having to leave your home. Several banks just announced that they are setting up banking services on the WWW. No longer will it require a trip to the bank to find out why your account balance is lower than your records indicate. Soon, you will be able to renew your drivers license, sign up for community events, watch first-run movies, and maybe even vote via the World Wide Web. One of the key technologies that will make this happen is coupling mature databases, such as the Oracle Relational Database Management System (RDBMS) with Web servers. Managing these large amounts of data using current methods is just impossible.

In order for commerce to be completely enabled on the Web, vendors need to be able to perform secure transactions. Although Netscape supposedly has the ability to perform secure or encrypted transactions, two computer science students at the University of California, Berkely were able to crack the encryption method. After learning of the problem, Netscape Communications, Inc., immediately posted a new version of software that fixed the flaw the students used to crack the encryption method. Although many users still feel safe using the system, not everyone will feel good about doing financial transactions over the Web until they can be completely sure about the security of their transactions.

When completely secure transactions are possible on the Internet, a reliable method of storing those transactions will be necessary. Currently those transactions are stored in relational databases. Rather than trying to recreate technology, companies will simply couple their Web applications with their RDBMS, as has already started happening.

Internal to Corporate Networks

Although I believe that it will take some time before the WWW evolves much past a larger version of what the online service providers currently have to offer, I do see some interesting things happening inside of corporations.

When I ran my own consulting company, I was in the business of putting together client/server applications. I generally worked with the smaller companies that did not have the means of investing in mainframe technology. With client/server computing, you leverage the desktop computer with the power of a smaller-than-mainframe-back-end-server. This is a great idea on paper as far as capital costs, but it is much more complex than the mainframe solution. Not only do you have to worry about application programming, you also have to worry about keeping two machines running rather than one, middleware that doesn't like your application or your network, early software that is so full of bugs it crawls, and so on.

I see Web technology replacing client/server computing in the very near future. Rather than having to worry about software on the client machine, simply install a Web browser. Rather than having to worry about middleware, just make sure the client and the server are running TCP/IP (the standard protocol on the Internet). Programming is reduced to writing HTML (which is discussed later in this chapter), often touted as being easier than any other computer language on the market.

I also see Web technology serving as an information system within the corporate environment. When you hire a new employee, rather than giving him or her a noteguide with all the company policies and practices, point them to the internal Web server. If you need to find out what the structure of the company is, look on the corporate Web server for the company organizational chart. Not only will the information get to those who need it, but it will be a lot easier to keep updated.

In order for this to happen, Web browsers and servers are going to have to be able to talk to corporate databases such as Oracle, Sybase, Informix, or DB2. Although HTML is easy to learn, the need to talk to databases is going to mean extensions. Those extensions are going to need rapid application-development tools to facilitate building Web applications.

Browsers are also going to have to be able to do some of the data validation on the client machine rather than just on the server. Right now if you want to fill in a questionnaire on the Web, you do so and then press a Submit button. This sends all of the information back to the server for validation. If the server encounters an error, it sends the browser to a new page mentioning that it encountered an error. Enabling the browser to perform validation functions will streamline the user interface, allowing client/server-type applications to be developed.

Now that you have an idea of what the World Wide Web is, let's take a look at PowerBrowser and how it can help you in your quest to become Web enabled.

PowerBrowser

In the next section of this chapter, you will be introduced to PowerBrowser and what it does. After listing the hardware and software requirements, installation instructions will be given.

What Is It?

Unlike browsers such as Netscape or Mosaic, PowerBrowser is not just a WWW browser. It also has some features that make it more generally useful, such as a design-layout tool and the ability to be a personal Web server. Oracle has also added some extensions to HTML that it is calling DBML (database markup language). These extensions provide database access, the addition of a BASIC scripting language, integration with the desktop using OLE, the ability of the browser to perform validation, and integration with the server-storing legacy data.

The way the current version works is that one program handles all three tasks (browsing, designing, and serving). When PowerBrowser is officially released, it is likely to be three separately executable programs, with the design and layout tool not officially being distributed. Oracle Corporation may ship an alpha version of it, then quickly follow it up with a more stable version.

PowerBrowser as a Web Browser

PowerBrowser is currently a Netscape 1.1-compatible browser. That means that all of the Netscape enhancements supported in version 1.1 are also supported by PowerBrowser. It also supports several new enhancements such as the database mark-up language (DBML) and Network Loadable Objects (NLO), which allow enhancements to be made to the browser dynamically.

Oracle is aggressively pursuing home-video-on-demand technology and has thus added the ability to play MPEG-decoded movies embedded within an HTML page. Due to bandwidth limitations, compression technology has not yet made this reliable over the Internet, but it is possible over standard Ethernet—which most corporate networks run on.

PowerBrowser is a product currently under active development; by the time you read this, there will probably be several other enhancements. The best place to go for up-to-date information about the browser is Oracle Corporation's Web site at http://www.oracle.com.

PowerBrowser as a Web Design Layout Tool

When you first start learning to create HTML pages (covered shortly), it seems relatively easy and straightforward—but it is a whole lot like being blind and driving a car by feeling the bumps in the road. In order to see what you have created, you have to load the file into your browser. By using PowerBrowser's designer, you can see the HTML document as it is created.

PowerBrowser as a Web Server

Creating a bunch of HTML pages is not enough to set up a Web server. After the pages are created, you need some sort of program that forwards those pages when browsers ask for them. Most servers run on UNIX machines. However, sometimes there may only be one or two requests a day for a particular page. Rather than dedicate an expensive and difficult-to-maintain UNIX machine, you can use PowerBrowser running under Microsoft Windows (3.1 or 95).

Hardware Requirements

PowerBrowser currently only runs under Microsoft Windows 3.1 and Windows 95. There are versions planned for UNIX using the X windowing system and an Apple Macintosh.

Currently it is a small program; if you can run Windows, you can run PowerBrowser. It takes about 3 MB of disk space, which is quite small compared to most Windows programs.

Because PowerBrowser is meant to be used on the Internet, an Internet connection is desirable (but not necessary). This connection can be through some sort of modem or a network connection. You also have the option of running on your own local area network, separate from the Internet. If no network or Internet connections are available, PowerBrowser can still display HTML pages from your local hard disk. The help files included with PowerBrowser will just be HTML pages stored on the local disk.

Software Requirements

To run PowerBrowser, you need to have either Microsoft Windows 3.1 or Windows 95 loaded on your machine. No additional software is required (except DOS with Windows 3.1).

Should you want connect to the Internet or corporate network through a network connection (for example, Ethernet), you will need a copy of TCP/IP software. It is included on the Windows 95 CD-ROM but needs to be purchased separately for Windows 3.1. Almost any WinSock-compatible TCP/IP software should work.

If you are using dial-up access, you will need a copy of serial line Internet protocol (SLIP) or point-to-point protocol (PPP). If you are using online services such as CompuServe or America On-Line, they generally include such programs with their browsers.

Installation

Installing PowerBrowser is a fairly simple process. If you are downloading it from the Internet, you currently have the option of saving the files on your hard disk, creating a single 1.44 MB disk or two 720 KB diskettes (as the program gets larger, more disks may be required). When you are downloading to two disks, you are prompted for the second disk.

After you have the installation disk (or disks), installation is as simple as running the self-extracting executable found on the disk. It asks you for the destination directory, then sets up a program group for you automatically.

The hardest part about installation is actually getting the TCP/IP software installed correctly. If you are sure that your networking software works fine, then PowerBrowser should not have any problems. If you do have problems, the best place to go for help is: http://www.oracle.com. Unfortunately, this assumes that you have a Web and an Internet connection. You can also send e-mail to torgo@us.oracle.com.

After the software is installed, you need to configure your preferences. This is done by going into the Options menu and selecting the Preferences... option. The first time you run this menu option, a Setup Wizard prompts you for information. You are given the chance of doing a Generic setup, an Oracle employee setup, or Portal Information Network Setup. Unless you are an Oracle employee, I suggest selecting the Generic setup. You are then prompted for your userid, your full name, and your e-mail address. After you fill in those fields, click on the OK button.

The next time you go into the preferences, you will notice that there is no Setup Wizard and that most of the preference options are filled in.

Navigating with PowerBrowser

The first thing you are going to want to do with PowerBrowser is surf the World Wide Web. After you play around a bit, you will want to customize your environment so that you can find your favorite Web addresses quickly. The purpose of this section is to explain that and then show you what else PowerBrowser can do as a browser.

Overview of the PowerBrowser Browser

Figure 54.1 shows the PowerBrowser browser looking at my newly created skiing home page. Notice how it looks slightly different than other browsers you may have seen. On the left side of the screen, you notice an area containing guidemarks and an area containing a history of the places you have visited. Because you can have more than one Web site open at a given time, Web sites are presented in their own child windows.


Figure 54.1. The Oracle PowerBrowser browser.

Going to Your Favorite Web Page

If you have not set up a guidemark with your own favorite Web site, you can specify the uniform resource locator (URL) address on the URL line shown in Figure 54.2.


Figure 54.2. Specify the URL (uniform resource locator) address on the URL line to have PowerBrowser take you there.

After you have entered the correct address, either press Enter or click on the GoTo button. To tell you that PowerBrowser is actually transferring data, the Oracle logo in the upper-right part of the screen rotates. If the address cannot be found, an error message appears.

Viewing Multiple Web Sites at the Same Time

As mentioned above, you have the option of opening multiple web sites at the same time. This can be done one of two ways. The first and easiest way is to click on the New button found next to the GoTo button on the URL line. This will open a new browser child window. You can then enter a new URL address in the new window and be in two places at once as shown in figure 54.3.


Figure 54.3. PowerBrowser allows you to see two Web sites at the same time.

How to Create and Use guidemarks

The World Wide Web is a big place full of all sorts of interesting sites. When you are surfing the Web it is nice to be able to get back to your favorite sites without having to remember the URL addresses (trust me when I say they are easy to forget). Figure 54.4 shows the guidemark section in PowerBrowser.


Figure 54.4. Here are some of the guidemarks that come with PowerBrowser.

Notice how guidemarks are stored in separate guides or guidemark folders. Rather than list all of your guidemarks together, you have the ability to classify them into separate categories. This makes it easier to find. Remember the Web is a big place and you may have hundreds of favorite sites, not just a handful.

To add a folder use the Add Folder menu option of the guidemarks menu. You are presented with the dialog box shown in Figure 54.5. Provide the name of the folder that you would like to create. If you check Add as child of selected folder, the new folder will be inside the currently selected folder. This enables you to have folders containing other folders. Once you have given the folder a name, click on the OK button.


Figure 54.5. The dialog box used to create new guidemark folders.

To add a guidemark to the currently selected folder, use the Add guidemark menu option in the guidemarks menu. The Edit guidemark Details dialog box shown in Figure 54.6 should appear.


Figure 54.6. The dialog box used to create new guidemarks.

Unlike adding a guidemark folder, adding a guidemark is slightly more involved. You are allowed to specify the name of the guidemark, which will appear in the guidemark subwindow on the left of your screen. Next, specify the URL address. I suggest making sure the URL address is valid by copying it from the URL line in the browser using CTL+C before opening the guidemark dialog box and then pasting it in the guidemark dialog box using CTL+V. Should you require it, you can specify the protocol and any extra parameters.

In the current version, it is important to use the Save guidemarks option in the guidemarks menu before exiting PowerBrowser. Otherwise, the guidemarks created during your session will be forgotten.

After you start using guidemarks extensively, you are going to want to do more than just add them. Editing and Deleting guidemarks and guidemark folders can all be done through the guidemarks menu.

Should you be migrating from Netscape and want to take all of your existing guidemarks with you, PowerBrowser has an option to migrate them; this obviates the need for you to recreate them. Simply select the Import guidemarks... option from the guidemarks menu; this brings up a file dialog box, from which you can choose the file that contains your current Netscape guidemarks.

The History List

During any PowerBrowser browsing session, you may come across one or two sites that merit going back to. If you will be going back continually, it is best to create a guidemark. However, if you will only be going back once or twice, it is better to use the history list as shown in Figure 54.7.


Figure 54.7. Use the history list shown here to go back to recently visited Web sites.

Unlike guidemarks, you do not need to manually add items to this list. PowerBrowser automatically keeps track of the Web pages you have recently accessed and lists them by page header on the left of your screen. To go back to a recently visited page, simply double-click on the name found in your history list. If the page is still in the cache or buffer, then it will load immediately. Otherwise, it will go out and reload that page for you.

After you are done with your history list, you have the option of clearing it out using the Clear option found on the Navigate menu.

In addition to being able to use the history list to revisit recent sites, you can also use it to audit where your browser has been. I am the father of three children, and naturally they like to use the Web. Although they are currently quite young and would never venture into questionable Web sites, I have the option of auditing where they go without having to stand over their shoulder. I make sure to clear out the history list before they start and then make sure it has a sufficient number of entries when they are done. Just knowing that I can do this will hopefully keep them from learning how to make fertilizer bombs in junior high.

Navigating within PowerBrowser

To help you navigate the Web, PowerBrowser has several options found on the toolbar as shown in Figure 54.8.


Figure 54.8. The toolbar found at the top of the PowerBrowser window.

If you place the cursor over a toolbar button and wait, tool tips will appear letting you know its function. Notice that the first three toolbar buttons (going from left to right) have to do with which mode you are in (Browser, Server, or Designer).

The next button enables you to load an HTML page from your disk. This is great for testing an HTML page that you have created before placing it on a server. Following this button is the one that takes you to your favorite home page. I'm an Oracle fan, so mine naturally points to the Oracle Web page.

The next group of two buttons enables you to go forward or backward. If you have been navigating through the Web and need some information from a previous page, use the back arrow to go back to it. After you have the information, use the forward arrow to go ahead to where you were before you went back. The arrows should be grayed out or disabled when there are no pages to go back or forward to.

The buttons following are used to reload a page or go back a whole level. Because I access the Web using dial-up lines, there is sometimes garbage on the line and large graphics may be garbled. When this happens I simply reload the page, and most of the time it comes through clean the second time.

Next is the Stop button. When loading a large HTML page or graphic, it is nice to be able to stop it using this button.

The last three buttons on the toolbar are used to copy, print, and get help. When you come across needed information in a Web page, it is nice to be able to print it out.

Sending E-Mail Using the Browser

When browsing the Web, you often have the chance to send e-mail to administrators of Web sites. PowerBrowser allows you to send mail by clicking on Send Mail... option in the File menu. Be sure that you have configured PowerBrowser so that there is an SMTP server, or it will complain.

Customizing the Environment

I was recently at a conference with two of my coworkers, and we all had the same exact laptop computer with pretty much the same software. Throughout the course of the day the laptops were continually being used, and it was amazing that, although one laptop may have been closer, each of us preferred to use our own. Why? Because each of us had configured our laptops to our liking. Although the developers of PowerBrowser have come up with some nice User Interface features, not everybody will like them. It is nice to be able to configure PowerBrowser to your own liking.

Configuring PowerBrowser is fairly straightforward. The first configuration that you are going to want to do is making sure that all of your preferences are set up correctly. This can be done by going into the Preferences option of the Options menu. It will then bring up the Preferences dialog box shown in Figure 54.9.


Figure 54.9. The Preferences dialog box allows you to change certain preferences.

Notice the tabs across the top. Five separate categories are listed: Proxies, User, Cache, Helpers, and Time-outs. When filling in the information for Proxies, it is best to talk to your system administrator to find out which values should be used. If you are the system administrator and don't know which values should be here, initially leaving them blank is probably the best thing to do. After you become more familiar with the Web and your network, it will become apparent which values you should use.

Setting the User Preferences

When installing PowerBrowser for the first time, you should have entered some of the basic user preferences. Figure 54.10 shows the user preference specification dialog.


Figure 54.10. This is where you specify user preferences for PowerBrowser.

The User ID, Full Name, and E-mail address should already be filled in. If you need to change any of this information, this is the place to do it. The Reply-To line allows you to specify a second E-mail address, should you want replies to your original to go someplace other than your original E-mail address. When it is left blank, the Reply-To defaults to your previously specified E-mail address.

PowerBrowser has used the default options for the rest of the user preferences, but you may change them in this dialog.

The Start with preferences determine what happens when PowerBrowser is initially started. The default is to not go to any page on the Web. The other option is to automatically load your home page. For those directly connected to the corporate network or the Internet, this is not a bad option. For those using dial-up lines (like me), it is nice to not have it connect to the home page immediately. Notice how there is a line where you can dynamically set your home page location.

The next set of options specifies the overall look of the HTML pages while you are looking at them. Notice that you have the option of looking at images while they are loading or only after they are done. You also have the option of changing your proportional and your fixed-width fonts. When you click on either of the buttons, the Windows font dialog appears listing all of the fonts you have on your system. This requires that you load the desired fonts onto your system before you can use them in PowerBrowser.

The next three, and final, options specify color settings. You have the option of dithering colors to match those in your color palette or just choosing the closest on the palette. The default is to dither, and I recommend this setting. Finally, you have the option to disable the palette control for images.

Setting the Cache Preferences

In the first half of 1995, the Client/Server Systems Division (now renamed the Web/Workgroup Systems Division) was responsible for putting on seminars throughout the United States. During the seminar, we demonstrated that you could use the Web to download trial versions of our software. Unfortunately we could not be guaranteed direct Internet connections at any of the seminar sites. This meant that we were required to use dial-up lines, and graphical images were drawn unbearably slowly. To keep the presentation interesting, the technical person responsible for the seminar would log onto the Net and run through all of the HTML pages that would be demonstrated before the presentation began. This had the effect of caching all of the images so that during the presentation, they were never downloaded. Unless you are doing something similar, you will probably never worry about the cache parameters in PowerBrowser.

The cache preferences screen is shown in Figure 54.11. The defaults should suffice for most users.


Figure 54.11. The PowerBrowser cache preferences or parameters.

The first preference actually tells where the home directory for PowerBrowser is. Unless you manually move files around on your hard disk after installing PowerBrowser, you should not have to change this parameter.

In the cache preferences, you have the ability to specify the cache directory, and how large it is. A one-megabyte cache should be large enough for most users. If you are frequently going between large pages with lots of graphics on each page and don't want to reload pages all the time, then you may want to increase the size to something larger. When we were doing the seminars program, eight megabytes was more than enough.

Next you have to option of specifying how often to reload pages and whether or not to temporarily disable the cache. The only time I have ever disabled the cache is when doing performance analysis on my own local network. Sometimes you want to get an average of how long it takes to load several pages, and so it is nice to be able to manually disable the cache. When browsing the Web for information, however, you will rarely have the need to turn it off.

Finally, you have the option of clearing out your cache immediately.

For most users, the cache preferences will rarely be altered. If you do need them changed, however, this is the area to do it.

Setting the Helpers Preferences

The Web is a dynamic place, making things possible today that weren't even thought about yesterday. Today it is common to see bit maps and text at most Web sites; tomorrow we will be seeing video and animation. In order to see this new media, PowerBrowser has the ability to specify helper applications.

Helper applications make it possible to process media types that are not currently built into PowerBrowser. For instance, some browsers cannot natively display JPEG files. To get around this limitation, these browsers utilize a helper application that is not built into the browser but allows you to see the JPEG image. In PowerBrowser, the Helpers preferences allow you to specify the helper applications that will be used to display or manipulate not-internal media types.

The Helpers Preferences dialog is shown in Figure 54.12. As you can see, PowerBrowser comes with several media types already specified.


Figure 54.12. The Helpers Preferences dialog.

The list area found at the top shows all of the preset media types with their command-line execute statements and media-type suffixes. If you click on one of the lines, more detailed information is shown below it. Because most of the helper applications come set up already, you should not have to worry about doing so here.

Setting the Timeouts Preferences

The final set of preferences, shown in Figure 54.13, has to do with timeouts. Timeouts settings specify how long the application waits before it decides to give up trying to perform an operation.


Figure 54.13. This is the Timeouts Preferences dialog.

As stated, all time-out values are given in milliseconds (1000 milliseconds = 1 second). Although the defaults may seem unusually long for most local networks, the Internet is much larger and requires it. The values that can be changed are

  • Name Resolution. This is the maximum amount of time allowed to translate the name of the Web site you are going to into a machine address.

  • Connection. This is the maximum amount of time allowed to connect to a Web site.

  • Command Response. This is the maximum amount of time allowed to respond to a command.

  • Read Data. This is the maximum amount of time allowed to start reading data from a Web site (an HTML page is data).

  • Write Data. This is the maximum amount of time allowed to start writing data to your own machine (notice how small the default value is).

  • Maximum Timeout. This is the maximum amount of time allowed for any given event, not previously mentioned, to happen.

The default values should be adequate for most users. If you find that you are consistently getting time-out error messages on more than one Web site, you may wish to increase some of the parameters. Remember to check out several Web sites, however. It is not uncommon on the Internet to have one or two machines shutdown for maintenance.

Where to Go for Help

If you get stuck using some of the PowerBrowser features, the first place to go for help is the online help provided. If, after going through there, you find that you still have questions, don't hesitate to mail us at torgo@us.oracle.com.

After you get your browser working correctly, the next question you may have is: Where do I go to find out about xyz? There are several good Web sites that act as lookup sites for URL addresses using keyword searches. My favorite is Yahoo, which can be found at http://www.yahoo.com.

Designing Web Pages

As with any software project, it is best to design what you are about to build before you go out and build it. The same is true with HTML documents. Even if you just sit down and sketch what the flow of the pages is going to be, you will save yourself countless hours of correcting mistakes.

After you have your design and are ready to build your Web pages, there are two ways that you can go: the hard way and the easy way. This is a teaching guide and, naturally, it would not be as emotional an experience to learn the easy way first. After you get disgusted with the hard way, then I will show you how PowerBrowser's built-in design tools make Web page creation simple and easy.

I will round out this section with a discussion of the database mark-up language extensions.

The Hard Way: with HTML

Hypertext Markup Language (HTML) is a subset of the more complete Standard Generalized Markup Language (SGML). It is used to describe the general format of a document. Although a language such as Postscript contains font and size information, HTML does not. Instead, it contains tags or format descriptions. It is then left to the viewing tool to choose the proper fonts and size (see the section on setting user preferences to see how to customize the fonts for PowerBrowser). Although most nonprogrammers may be scared away from HTML when they hear it is a language, it really is quite simple.

A Simple HTML Page

Perhaps you want to give the title name for your page and a short description of what can be found there. This can be done by entering the following into a text editor (the notepad included with Microsoft Windows can be used) and saving it to a file with the .asp extension: 

<title> Matt's Wonderful World of Skiing </title>

Matt's Wonderful World of Skiing

This produces the output shown in Figure 54.14. It is not the most exciting page you have ever seen, but then again it is only a start.


Figure 54.14. This is the result of the simple HTML listing.

In HTML, there is often the tag that marks the beginning of the text to be formatted and a closing tag to mark the end. In this case, I used the <title> tag to set the appropriate title of my document. Any other text that is not encompassed in a format tag set is displayed as normal body text.

It would be nice to display "Matt's Wonderful World of Skiing" as something other than just plain body text. To display it as a header, you can surround it with the tag set <h1> . . . </h1>. There are six levels of header tag sets. Thus you can choose from <h1> or <h2> . . . to <h6>. Let's add a heading and some more text to the HTML listing just created. 

<title> Matt's Wonderful World of Skiing </title>

<h1> Matt's Wonderful World of Skiing </h1>

For those that like to ski . . . this is the place to be.

The result is shown in Figure 54.15.


Figure 54.15. The result of adding a heading to the simple HTML listing.

You will notice that with HTML, white space (Tabs, spaces, and carriage returns, for example) has no meaning to the formatter. You could list a single word on each line and PowerBrowser will string them together to form sentences and paragraphs. However, sometimes you will want carriage returns to separate your paragraphs. This is done with the <p> tag. Just place <p> every time you wish to print a carriage return.

Character Formatting in HTML

Now that you understand some basics about HTML, let's get a little more creative. One of the most important differences between HTML and plain ASCII text is the ability to place emphasis on words by making them bold or italic.

To add bold typeface to words in the continuing example, simply place <b> . . . </b> around the desired words. 

<title> Matt's Wonderful World of Skiing </title>

<h1> Matt's Wonderful World of Skiing </h1>

For those that like to <b> ski </b> . . . this is the place to be.

Italic is very similar to bold; the tag set consists of <i> . . . </i>. 

<title> Matt's Wonderful World of Skiing </title>

<h1> Matt's Wonderful World of Skiing </h1>

For those that like to <b> ski </b> . . . this is the place to <i> be </i>.

Your HTML page should now look like the following:


Figure 54.16. The simple HTML example with bold and italics added.

While the bold and italics typefonts are supposedly replacements for underlined text, it is still nice to be able to underline on occasion. A new standard that is emerging in HTML is to use the <u> . . . </u> tag for underlining. PowerBrowser naturally supports it.

PowerBrowser also supports the ability to embed fixed-width fonts into documents. Because the typefont is different than the normal body text font and more closely resembles the old character-based displays of DOS, I like to use it when giving instructions on what to type into the computer. The tag set is <tt> . . . </tt>, where the tt is short for "typewriter text."

Embedding Images in HTML

Rather than bore you with more text formatting, let's move onto something more interesting, like displaying images in an HTML document (we will cover more text afterwards).

PowerBrowser can display GIF and JPEG images within an HTML document. To display an inline image (an image next to text within an HTML document), use the tag <img src=filename>. Make sure you substitute the correct image filename in place of filename.

To place a picture of a man skiing in our HTML document, we would change the listing to the following: 

<title> Matt's Wonderful World of Skiing </title>

<h1> Matt's Wonderful World of Skiing </h1>

<img src=manski.gif>

<p>

For those that like to <b> ski </b> . . . this is the place to <i> be </i>.

Notice how I added the paragraph tag. Without it, the text would appear to the right of the inline image. The resulting HTML page is shown in Figure 54.17.


Figure 54.17. This is the HTML page with an inline image.

Indenting, Bullets, and Numbering in HTML

The next goal in creating my Web page is to have a listing of my favorite places to ski. To make the layout more pleasing, I would like to indent a bullet list. This is done with the indenting tag <ul> . . . </ul> and list tag <li>.

To present my favorite places to ski as a bulleted list, I would use the following: 

<h2> Matt's favorite places to ski </h2>

<ul>

<li> Snowbird, <b> UT </b>

<li> Alta, <b> UT </b>

<li> Solitude, <b> UT </b>

<li> Mammoth Mountain, <b> CA </b>

<li> Vail, <b> CO </b>

<li> Squaw Valley, <b> CA </b>

</ul>

If I then wanted to add a numbered list of my all-time favorite skis, I would use the indenting tab <ol> . . . </ol> with the list tag <li> as shown here. 

<h2> Matt's all-time favorite skis (in order) </h2>

<ol>

<li> Research Dynamics, Puma

<li> K2, SLC

<li> Rossignol 4S

</ol>

The results of these two additions are shown in Figure 54.18.


Figure 54.18. The Web page with a bulleted and a numbered list.

Notice that with both lists, the list-item tag (<li>) remains the same. Only the indenting tags change.

Hypertext Links in HTML

The next major feature of HTML is that of hypertext links. Not only do you have the option of going to another section of the current document, but you also have the ability to jump to other documents. In the preceding example, I listed my three all-time favorite skis. Rather than just list them, it would be nice to have a hypertext link further on in the document explaining the significance of each.

Providing links in the current document is done by assigning a label or destination and then providing the jump line. The label or destination is assigned with the tag: <a name="destination"> . . . . Because it is a unique destination, a unique destination name must be given in the opening section of the tag. There is an area for text and then the closing section of the destination tag.

Providing the jump-to link is done with the following tag: <A HREF="#destination"> . . . </A>. Notice the use of the number symbol (#). Whatever appears between the opening and closing section of the tag is highlighted and serves as a place for the user to click to use the link.

In our example, links can be provided in the current file by adding jump-to and destination tags in the following manner: 

<h2> Matt's all-time favorite skis (in order) </h2>

<ol>

<li> Research Dynamics, <a href="#PumaLink"> Puma 

<li> K2, <a href="#SLCLink"> SLC </a>

<li> Rossignol, <a href="#4SLink"> 4S </a>

</ol>

<a name="PumaLink"> Puma </a> <p>

When I was 14, I wanted . . .

<a name="SLCLink"> SLC -- Traditional construction </a> <p>

I like a good traditional ski as opposed to a "cap" ski  . . .

<a name="4SLink"> 4S </a> <p>

A buddy of mine borrowed these  . . .

Because you do not want to make your HTML pages too large, you will often want your hypertext links to jump to places in other documents. This is done by adding the second HTML page file name to the href section of the jump-to tag: <a href="file#destination"> . . . </a>. The destination file must have a destination tag.

You also have the option of creating hypertext links to Web pages on separate computers. In this case, replace the file#destination reference with the URL address.

I have not tried to give you an exhaustive HTML tutorial. Instead, my goal was to highlight its simplicity. You should be able to create simple HTML pages if you desire.

Using the PowerBrowser Design Tool

If HTML is so easy, then how come working with straight HTML is considered the hard way? As with any new concept, the initial learning steps may be easy or hard. HTML just happens to have fairly simple initial learning steps. Once you get past simple formatting, however, HTML becomes much more complicated, and a good layout tool can aid you dramatically.

Currently, the PowerBrowser design tool is under construction and most likely will not ship with the first release of the production version. To give you an idea of what you can do, however, Figure 54.19 shows what it currently looks like.


Figure 54.19. PowerBrowser's current design tool.

Notice that in addition to text and images, you can place fields, button, checkboxes, and radio buttons on HTML pages (things I didn't cover in the HTML minitutorial). There is also something similar to a property sheet found on the left side of the screen. The combination of these features allows you to build client/server applications with Web technology similar to using Oracle Power Objects.

As with Power Objects, PowerBrowser uses the familiar drag-and-drop metaphor to get things done. After you place text areas on your pages, rather than having to type the text in by hand, simply drag the text file from your file manager and drop it into the text area. This enables you to prepare text using your favorite editor.

Using the Layout Wizards

In addition to the Design tool, PowerBrowser also contains layout wizards or templates. Rather than having to design Web pages from scratch without any help, you will have several layout styles to choose from. If you are building an electronic catalog Web page, you will be able to bring up the Layout Wizard for catalog Web pages. After specifying several important pieces of information (such as where the picture and description of your catalog items exist electronically), PowerBrowser automatically generates your HTML for you. You then have the option of going in and modifying it to your liking.

The only Layout Wizard that currently exists is one to generate a personal home page. Simply provide information about yourself, including a picture, and it generates a nice home page.

DBML Extension Overview

There are some rather large Web sites on the Internet. There are some even larger ones, however, that are not accessible by the public Internet community because they reside within corporate networks. One such site that I have worked with currently has over 300 HTML pages. Making sure that those pages contain current information by editing the HTML is a nightmare. A better way to administrate is to pull information out the database and dynamically create HTML pages from that.

Using a database with HTML requires that some extensions be added. Oracle's extensions are known as the Database Markup Language (DBML). These extensions allow for Oracle Basic (the same Basic engine supplied with Oracle Power Objects) to be embedded into HTML documents. New methods specific to PowerBrowser have been added, and the ones specific to Power Objects have been removed.

In addition to the ability to access databases and embed BASIC within HTML documents, DBML also allows for tighter integration with the desktop using Microsoft's object linking and embedding (OLE).

Going over the DBML extensions in detail is beyond the scope of this chapter. As PowerBrowser is released, the best place to go for the DBML specification will be http://www.oracle.com.

PowerBrowser as a Server

In addition to being a browser and an HTML layout tool, PowerBrowser can also act as a personal server. Starting the personal server is as simple as clicking on the Personal Server button found on the toolbar, setting up the correct home page, and then clicking on the Start Server button found on the toolbar.

Having the ability to serve Web pages from your personal machine solves several problems. First, you can edit your HTML pages locally, and you don't have to worry about copying them onto another machine. Second, you don't have to invest large amounts of time and money setting up a dedicated Web Server running UNIX or Windows NT.

Summary

In this chapter, you learned how to use Oracle's PowerBrowser as a browser and how to create simple HTML documents. You had a preview to the design and layout tool as well as an overview of the DBML extensions to HTML. You also read about how to turn PowerBrowser into a personal Web server.

Most users of PowerBrowser will use it to replace their Mosaic or Netscape browser. As the world becomes more Web enabled, it is hoped that the need for Web-authoring tools and personal servers will make PowerBrowser a very attractive solution.

It was my hope to give you a preview of a work-in-progress. By the time you read this in the guide, PowerBrowser will have evolved to be even more powerful. Because no software product is ever complete, I welcome your comments (both on the software and on the content of this chapter). I can be reached via Internet e-mail at mbennett@us.oracle.com or on Compuserve at 75120,2747.

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