Learn More About XLiRAD

Overview

XLiRAD makes it easy to add database interactivity as you author Hypertext Markup Language (HTML) pages. With XLiRAD you can:

Insert information into databases on multiple computers (subject to the number of licenses you purchase).
Pass information from one page to another to maintain state and return information from the database as formatted HTML tags.
Design the display of data using tables, drop-down select lists, radio buttons, check boxes, tree lists, and mailing address formats.
Use conditional branching to determine the appropriate page to display based on values in your database or data entered by the user.
Include your own custom Java routines or third-party Java functions.
Ensure that data entered on the Web pages matches the data types in your database using XLiRAD's built-in data validation.

Because site design with XLiRAD does not require advanced programming skills, you can launch a simple site in minimal time. Because of its flexibility in supporting customized plug-ins and other features, XLiRAD also enables experienced Web developers to create complex sites while incorporating database access easily and efficiently.

Web sites designed with XLiRAD provide a superior user experience due to:

Maintaining persistent database connections to ensure fast query response.
Paging once through large result sets for greater efficiency.

XLiRAD is compatible with all browser platforms and with Web technologies such as Dynamic HTML (DHTML), Extensible Markup Language (XML), JavaScript, multimedia effects, and plug-ins.

Sites developed with XLiRAD can run on Microsoft Windows NT, UNIX, Linux, or Apple Macintosh platforms.

For information about how XLiRAD supports the features described in this section, see Components.

Components

XLiRAD consists of these server-side and client-side components. Server components reside on the computer that runs the Web service; client components can reside on any computer that supports the Java run-time environment and has network access.

Component	Client	Server
DBServer		X
FormProcessor		X
SQLEditor	X
TemplateMaker	X

DBServer Overview

DBServer manages all communications between the database and the Web clients that download pages from your site as well as the authoring clients used to design Web pages published on that site. DBServer supports connectivity and reliability by periodic self-testing of ports and database connections and continuous logging of events such as client requests and server responses. In addition, DBServer supports security through account and password combinations, and through defined user groups that control access to specific SQL statements.

For more information about working with DBServer, see:

FormProcessor Overview

FormProcessor is a server component that:

Receives templates from the servlet manager.
Works with DBServer to obtain data from the database.
Interprets the custom command tags such as <CMD> and <REP> to display XLiRAD templates in the Web browser.

FormProcessor functions internally and requires no user interaction beyond configuring interoperability with the servlet manager software. For more information, see Install XLiRAD Clients.

SQLEditor Overview

With SQLEditor you can enter SQL statements that include the values passed to the database through your templates and specify the database used.

SQLEditor connects to the computer running DBServer and stores SQL statements on that computer. From there any user who is a member of a group with rights to a statement or range of statements can use the statement.

For more information about SQLEditor, see Work with SQL Statements.

TemplateMaker Overview

With TemplateMaker you can create templates that include HTML styles such as tables, select list boxes, radio buttons, check boxes, and so on. These templates can incorporate SQL statements created in SQLEditor by calling the appropriate command ID. The template specifies the formatting and style for presentation of the result set returned by the SQL statement.

Because templates reside on the computer running DBServer, any XLiRAD user has access to them. TemplateMaker, in conjunction with DBServer, provides version control on template files, so that only one user can work in a template at a time.

You can create the initial HTML page in any HTML editor before importing it into TemplateMaker for integration of the SQL statements. As a result, template pages can include images, frames, or multimedia effects and the template syntax does not interfere with those elements.

For more information about TemplateMaker, see Work with HTML Templates.

Interactions

In the following diagram, notice the flow of communications through the XLiRAD components and other systems. The diagram assumes that you have started DBServer and that DBServer has connected to the HHPN site for validation.

DBServer communicates with the TCP/IP port for the computer hosting the database and makes a connection to the database, using data stored in the server configuration file. DBServer uses JDBC or ODBC drivers for this database connection. DBServer persistently maintains that connection as it runs.
During site development and testing, users writing SQL statements with SQLEditor and designing templates with TemplateMaker communicate with the server computer's TCP/IP port and connect to DBServer to save their new or updated files or to view other files authorized for their group.
When companies post their sites to the World Wide Web, clients display an HTML page that includes a POST method to the servlet manager with the template name as the INPUT value.
FormProcessor interprets the template, locates the commands it contains, and connects to DBServer.
DBServer communicates with the database to process the specified SQL statements and passes the statement result set back to FormProcessor. FormProcessor replaces values requested in the template with retrieved data. DBServer caches the entire data set rather than data for an individual page.
If the page calls user-defined external functions, FormProcessor also processes these before resubmitting the page to the Web server by means of the servlet manager.
The Web server displays the information to the browser client according to the custom tags and formatting defined.