Oracle Designer 2.1.2 WebServer

Oracle Designer 2.1.2 WebServer –

A New Generation of HTML pages

Bonnie Vermillion, Dulcian, Inc.

Overview

The Oracle Designer 2.1.2 WebServer Generator enhancements bring flexibility, adaptability and control to the creation and maintenance of the resulting HTML pages. The following new features have been added to make the creation of HTML pages easier and more visually interesting.

The ability to divide the resulting HTML pages into frames greatly enhances the usefulness of creating Web pages from Designer. This technology provides the ability to use partitioned areas of the resulting page as desired instead of being limited by the generators’ standard layout metaphor. This flexibility also permits the designer to provide multiple page types on one resulting page, thus eliminating the restriction of displaying multiple resulting pages. For example master/detail results can be shown on the same page.

Style sheets are another method available to enhance the appearance of WebServer Generator Applications. Colors, fonts, and other visual effects can be applied to WebServer Generator applications using preferences.

Customized templates provide the ability to standardize the look and feel of the WebServer application. Preferences and layout can now apply a consistent look and feel to multiple Web pages within an application and across applications.
This paper will discuss the first two of these new features in detail.

Frames

The use of frames in delivering Designer 2.1.2 WebServer Generator applications is a new feature that provides an alternative to the traditional multi-page metaphor used in previous versions of Designer. The use of frames enables the types of WebServer Generator pages generated to be shown on one layout page in defined sections.

Default Frames

The default frame layout provides a mechanism to ensure that each application is formatted in the same way wherever it is applied. It also provides the ability to show all types of output on one page. Below is a replication of the default frame layout as defined in the Oracle Designer documentation. This default frame layout will appear unless the Module Component is designated as having a Layout Style of "LIST" on the Property Sheet or the Module Component is not a detail module. The LIST form indicates that the output appears on individual pages. You should designate Module Components as LIST when the browser does not support frames or when the amount of output information is too large for frames to handle.

FraTOP page header, title, default text area, and query
FraRL Contains the Record List
FraVF

Contains the View and Insert Forms
FraBOTTOM Contains the Page Footer

Custom Frames

Custom frames are a welcome addition to the functionality of the WebServer Generator. Control of layout pages provides flexibility delivering Web applications with Designer 2.1.2. Custom frames extend the functionality of default frames allowing designers to develop custom layouts to fit the needs of any application. By developing your own default custom frames, all of your applications can utilize these frames to achieve a consistent look and layout.

Defining and applying custom frames

In order to define and apply a custom frame, start by determining the desired frame layout. Next, create an HTML file that stores the frame definition. An example of a custom frame is shown below.

This frame is created by defining an html file with the following contents:

A quick lesson on the HTML FRAMESET and FRAME tags will provide a better understanding of the contents of the frame file using the following steps
The FRAMESET tag defines the width and height. The COLS and ROWS attributes determine the size. If two numbers are used separated by a comma, then the frame will become the designated size in pixels. If instead a percent is used, both values can be set to add up to 100%. When a percent is used with a ‘*’, the size will be determined in relation to the size of the browser window.
The FRAME tag is used between the FRAMESET tags to define the contents for each frame window defined. The names F1, F2 and F3 will be used within the Module and Module Component preferences to link the specific output to each frame.
Store the frame file in a directory on the Application Server.
Log into Designer and either open an existing WebServer Module or create a new WebServer Module. If a new WebServer Module is being created, it is best to use the Module Component Data Wizard under the Tools Menu Item as shown below. Using the Wizard proves beneficial especially when creating Master/Detail Module Components. The Wizard will enter the correct defaults, link the detail Module Component to the Detail, and will save time in undoing or redoing Master/Detail Module Components.
Once the Module Components have been created; generate and run the module to make sure the module works. Modifications will now be made to the preferences at the Module Level as follows:

FRAMES	PLACE QUERY FORM ON SEPARATE FRAME	NO
	AUTO QUERY VIEW FORM	YES
FRAMES – CUSTOM	TEMPLATE FILENAME	e:\framecustom.htm
	QUERY FORM FRAME	F1
	RECORD LIST FRAME	F2
	VIEW/INSERT FORM FRAME	F3
RECORD LIST	ADD DETAIL HYPERLINKS TO RECORD LIST	YES
STARTUP PAGE	ABOUT PAGE HYPERLINK REQUIRED	NO

By defining the preferences at the Module Level they will automatically be applied to the Module Component level.

The first preference enables the Query Page to be displayed on the framed page.
The next preference tells the generator to automatically query the View Form after the record is selected from the Record List Form.
The 1^st custom preference relays the filename of the custom frame file to the generator.
The remaining custom preferences link the frame type to the corresponding frame window as defined in the custom html file with the FRAME tag.
The Record List preference allows the detail Module Component Record List to be shown on the same frame with the Master View Form.
The last definition eliminates the about page link.

In addition to the preferences defined above, in order to display the detail Record List with the master View Form, the detail Module Component properties must have all Bound Items as Query = NO in order to not generate a query form for the detail Module Component. The Master Module Component must have the Layout Style Property set to "LIST/FORM" and the Detail Module Component must be set to "LIST" for the same property. Also, remember that Preferences set at a higher level will filter to lower levels. It is recommended that Preferences be defined at the highest level possible. This will save time in duplicating the effort in defining them at a Module Component Level and again at a Module Level.

Any time that a change is made to the custom frame HTML file, the module must be recompiled since the WebServer Generator pulls the file in at compile time only. If the Module Component is built outside of the Wizard, there are many problems that can arise from properties not being defined correctly especially when attempting to show a master/detail on one page or window. As mentioned earlier, using the Wizard will save time. The page below is an example of a master/detail shown in one window.

Using Style Sheets with the WebServer Generator

Another new feature that is useful to use with the WebServer Generator is style sheets. Style sheets are a way to improve the appearance of your Web page. These style rules tell a browser how to display its contents. Now style sheets can be linked to the WebServer Generator.

There are some issues to be aware of in the use of Style Sheets with the WebServer. First, the browser being used is very important since only the latest browsers correctly interpret the style rules. Second, the WebServer currently has limited use of Style Sheets compared with direct links to HTML files.

Style Sheets are created as files that have a .CSS extension. The file contains code indicating fonts, colors, and other formatting definitions such as bold and underlining. To learn more about style sheets, use the links provided in the WebServer Documentation provided from Oracle, or simply perform a search on the Internet. Below is an example of style sheet contents.

The style sheet file above links the attributes defined to the tags indicated. The definitions are contained within the STYLE tag. Below is an example of how to link a style sheet file to Module Preferences.

In the example above, the style sheet is linked to the Record List page. The same style sheet can be linked to the other templates. Additional style sheets can be created and linked to different pages to give each frame a different appearance. Below is the result of the style sheet link using Netscape Communicator 4.5.

Internet Explorer 5.0 displays a slightly different appearance.

There are many other interesting ways to use style sheets in conjunction with HTML. Using style sheets within STYLE tags is the only current successful method to link style sheets to Designer WebServer Modules. This method is obviously useful and makes it easy to add "style" to the plain pages generated by the WebServer Generator.

Keep in mind the limitations of the browser. For example, Internet Explorer 4.0 was not able to run the page with the style sheet link and instead displayed a message to that effect. As evident in the examples, style sheets do cause pages to appear differently based on the browser even though the page content remains the same.

Summary

Frames and style sheets add flexibility to the WebServer Generator without degrading performance. The limitations for use within Designer restrict usability to a degree; however, there are still benefits in incorporating these features. Even though Custom Frames are not usable in the realm of a master/detail/detail relationship, the ability to display a master/detail relationship on one page is very useful. The ability to show multiple layout types on one window is another benefit of this new feature.

Despite their limited use within Designer, the fact that Style sheets can be used at all is a useful addition to tool functionality. The possibilities for future releases can be realized in the expansion of these types of features. Although the visual features of a WebServer Generator application are not always important, the capability of Designer to produce Web pages that can display features that exist with other Web tools is an important step in closing the gap with other products and making WebServer Generator a viable competitor.

About the Author

Bonnie Vermillion is a Senior Developer with Dulcian, Inc. She has been an Oracle Developer for over 10 years with the Federal Government including 3 years with the Federal Trade Commission. She has 4 years experience working with Designer/2000 (now Oracle Designer) and serving as CASE administrator. Bonnie has given presentations at ECO, ODTUG, and numerous local Oracle user group meetings. She can be contacted at bvermillion@dulcian.com or through Dulcian’s Website at www.dulcian.com.