Figure 21.9.
Example of PL/SQL
stored procedure that
generates dynamic
HTML.

Developer/2000 for the Web

In May 1997, Oracle Corporation announced the production release of Developer/2000 for the Web, release 1.4W. At the time this book was published, a trial version of Developer/2000 for the Web could be downloaded from the Oracle Web site. However, be warned—the Developer/2000 release 1.4W download file is 159MB and expands to almost 500MB. This section will focus on the Windows NT version of Developer/2000 for the Web (it is also available for the Solaris operating system).

Developer/2000 for the Web supports the deployment of Oracle Forms and Oracle Reports applications as Web applications. Developer/2000 requires the use of either the Oracle Web Server 2.1 or the Oracle Web Application Server 3.0. Developer/2000 for the Web includes a new component, the Forms Server Listener, that must reside on the same server with the Web Application Server. Let's take a closer look at the architecture in Figure 21.10.

Figure 21.10.
Architecture Support-
ing Developer/2000
for the Web.

As you can see in Figure 21.10, the architecture consists of three tiers:

• The Forms client, which consists of a Web browser that downloads the forms application as a Java applet
• The application server, where the Web Server and Forms Server Listener both reside
• The database server, where the Oracle database that supports the Forms application

The client machine only requires a Web browser that has been Java enabled (specifically, it must support the Java Development Kit 1.1.2 or higher). The user enters a URL that contains the following:

• The name of the application server
• The port that the Web Listener is monitoring
• The name of the Web application
• The name of the module
• The user ID and the database alias

The application server (Solaris and Windows NT are currently supported) contains these components:

• Oracle WebServer 2.1 or Oracle Web Application Server 3.0
• Forms Server Listener
• Java Development Kit (JDK) 1.1.2 or higher
• Oracle Forms .FMX files and Oracle Reports .RDF files

The Forms Server Listener is responsible for reading the .FMX file referenced in the URL and downloading the necessary Java classes and applet to mimic the functionality that the form provides in a client/server environment.

Finally, the database server hosts the Oracle database that is accessed by the Forms Web application. Of course, the Oracle database could reside on the application server.

Configuring Oracle Forms for the Web

To configure Oracle Forms for the Web, you need to perform three tasks:

• Generate and deploy the Oracle Forms .FMX files on the application server.
• The Forms Server Listener must be started on the application server.
• The WebServer must be configured so that the Forms application is available to the client machine. Refer to the Developer/2000 for the Web Installation Guide for further details.

Let's look at the detailed steps needed to complete each task.

Generating and Deploying Oracle Forms .FMX Files

When you install Developer/2000 for the Web, release 1.4W, Oracle Forms 4.5.8 is also installed. For each .FMB file that you want to run as a Forms Web application, you must regenerate the .FMX file using Oracle Forms 4.5.8. If there are no errors during the generation of the .FMX file, place the .FMX file on the application server. You can place the .FMX files in any directory on the application server as long as you specify the directory path and filename in the cartridge or HTML file that users reference to run the Web application.

Invoking the Forms Server Listener

The Forms Server Listener must be running before a user can run an Oracle Form as a Web application. There are two ways to invoke the Forms Server Listener on Windows NT:

• You can choose Start | Programs | Developer/2000 for NT | Forms Server Listener.
• You can choose Run, enter C:\ORANT\bin\f45srv32 port=5555, and click OK.

To verify that the Forms Server Listener is running, move the mouse so the pointer is on a blank region of the Taskbar and right-click Task Manager from the popup menu. Select the Processes tab and scroll through the list of processes. If the Forms Server Listener is running, you will see a process named f45srv32.exe in the list.

Running a Form from the Applet Viewer

To make the applet viewer available on the client machine, you will need to install JDK 1.1.2 which is available on the Developer/2000 for the Web CD-ROM. By default, JDK 1.1.2 will be installed beneath the Oracle home directory as JDK1.1.

You should also set two system variables:

• CLASSPATH, which should be set to C:ORACLE_HOME\jdk1.1\jdk\lib\classes.zip (where ORACLE_HOME is the directory where the Oracle products are installed on the application server).
• PATH, which should include C:\ORACLE_HOME\jdk1.1\jdk\bin (where ORACLE_HOME is the directory where the Oracle products are installed on the application server).

To run the applet viewer, you will need to open a DOS window on the client machine.

Development Considerations Regarding
Developer/2000 for the Web

If you or your organization are already using Developer/2000 to build client/server applications, Developer/2000 for the Web offers a direct path to deploying your Oracle Forms and Reports applications as Web applications (subject to the caveats discussed in the previous note). On the positive side, Developer/2000 for the Web enables you to avoid the burden of coding a Java applet that has the equivalent functionality as your Forms or Reports application. On the other hand, with Developer/2000 for the Web, you have little control over the Java code that is generated; it may be quite difficult to integrate a Forms application with other Java applets. However, if you aren't currently using Developer/2000 and have no plans to begin using it, there are other alternatives available to you:

• Develop PL/SQL subprograms using PL/SQL packages supplied with the Web Application Server to dynamically generate HTML
• Develop a Java applet using a Java development environment such as Symantec Cafe
• Use third-party software packages such as Cold Fusion or Tango that enable you to access an Oracle database via ODBC

Let's look at the advantages and disadvantages of these alternatives.

Developing Web Applications with PL/SQL

Oracle's Web Application Server includes several packages, including htp and htf, which you can use to construct a Web application. There are several advantages to this approach:

• Because you are using PL/SQL to code your application, you have access to all the built-in packages and other capabilities of the Oracle database.
• With the responsibility of coding each Web form, you also have control over the appearance and behavior of your Web application.
• Through the use of the Web Application Server 3.0 PL/SQL Cartridge, you can ensure that transactions are properly rolled back or committed.