PalmPilot: The Ultimate Guide, Second Edition

Appendix D. Writing a Palm VII Query Application (PQA)

—written by Dave Menconi,Palm Clipping Project Lead, Palm Computing

As explained in Chapter 16, a Palm Query Application (PQA) appears to the Palm VII owner as just another application, much like the Memo Pad or Calculator. But in reality, it’s a database that’s given special treatment by the operating system. When you tap it, the operating system opens it with a program you can’t see (called Clipper, although you’ll never actually see that name displayed).

In addition, a PQA is different from other applications in what it can do. It can collect and display information, but it can’t process information like most programs. Since it connects to the Internet, its inability to actually crunch data is not as great an impediment as it seems—there are literally thousands of computers that can do processing for you!

A PQA usually consists of a form (or query) that you’re supposed to fill out. The Palm VII sends the form data to a server on the Internet, which processes the query and returns information in the form of a tiny web page. But that’s not the only use for PQAs, as you’ll see in this appendix; a PQA can also serve as a single-screen application launcher or even as an illustrated, attractively designed electronic book, complete with tappable hotlinks to other chapters (or even other PQAs).

This appendix provides a brief overview of making your own PQAs. This discussion assumes that you know what HTML is, that you’re able to ...