Building Web Applications with dBASE Plus

dBASE Plus includes a set of powerful tools for developing web applications. This Tutorial is an introduction to developing web applications with those tools. The Tutorial contain ten Sessions. We begin with an overview of how Common Gateway Interface (CGI) programs work and how to configure a web server so that it will process these programs.

The next Session focuses on producing web applets with the dBASE Plus Web Wizards. These Wizards offer a set of tools that will write your program code and create the applets to run on your server. Although you can produce some basic application with the Wizards, you will soon want to move on to customizing your applications.

Session Three discusses the use of CGI environment variables, which is the primary way your web server sends data to your CGI program. Following this, Sessions Four and Five focuses on the anatomy of a dBASE Plus CGI program. Session Four explores the use of the dBASE Plus WebClass library and Session Five explores the nature of a CGI response page.

The next two Sessions explore how you might move your applets beyond what the Web Wizards offer. Session Six focuses on remote data editing and Session Seven focuses on creating dynamic Web reports. These Sessions are followed by two special topics. The first, found in Session Eight, looks at how HTTP Cookies are used to create a persistent state in a Web Application while the second special topic, found in Session Nine, looks at transferring binary data between a web browser and a web server.

The Tutorial concludes, in Session Ten, with a Hands-on project where you will create a full Web application. The Tutorial WebStore is a simple shopping cart application where the shopper can browse a catalog of items, add an item to their cart, modify their cart and checkout.

New in the Second Edition

A significant number of enhancements have been added to the Second Edition of the dBASE Web Tutorial.

  • Session One now includes an overview of CGI technology. Here we discuss how data is passed from a web browser to a CGI program and how that program sends data back to the browser.
  • Session Two adds an example exercise for the Query and Response Wizard and a second exercise for a drilldown report. There are now five example exercises in this Session.
  • Session Three is new to the Tutorial. It discusses CGI environment variables and how to use them in dBASE CGI program.
  • Session Four (Remote Data Entry) now incorporates an updated text of my dBulletin article "Building a Web Application with the Web Classes." In addition, the example exercises have been updated to work with dynamic external objects (DEO). At the end of the Session there are now samples of HTML form elements.
  • Session Five (Response Pages) adds new discussion of the CGI header,
  • Session Six (Remote Date Editing) incorporates an updated text of the last part of my dBulletin article on "Building Web Applications."
  • Session Seven (Web Reports) has been greatly expanded. It now includes a brief discussion of HTML tables and their attributes. A new Exercise shows how to add a HTML table to a CGI response page. The Web Reports library has been enhanced to handle groups, drill down options and additional formatting option. This Session incorporates an extended discussion of this library based on the recently published dBulletin article "Creating Reports for the Web:"
  • The Special Topics Session from the first edition has been divided into two Sessions. Session Eight (Special Topics: Cookies) includes an enhanced discussion of HTTP cookies and their specifications. Session Nine (Special Topics: File Transfers) includes a much enhanced discussion of HTTP file uploads and adds a discussion of HTTP downloads.
  • The hands-on-project, now in Session Ten, has been redesigned so that now it utilizes DEO. The application now runs from a single program file. In addition the ability to delete or modify items in a shopping cart has been added to the program. Session Ten has been updated to reflect these design changes.
  • Also added to the Tutorial are two Appendices of HTML Tag References, one for the Form tag and the other for the Table tag.