J P Seagle 2/26/98

In Class on February 25 I demonstrated use of an Object Database Management System called POET. This is a summary of how you can get a copy and work with it.

The software can be downloaded from http://www.poet.com. It is evaluation software, but fully featured and may be used indefinitely for academic use in teaching or projects, but not for commercial or administrative use. You must register online before downloading.

The database system download file is ptkernal.exe (4688k). It is a self extracting executable that throws a bunch of files in your computer under the POET50 directory. To use it, you also need a software development kit. The choices include JAVA, C++, and ActiveX (Visual Basic). One of these should be run after installing (executing) the database files. I have tried JAVA (2226k), and it adds many more files and directories under poet50.

The downloaded files can be deleted after being run. If you have a slow modem and do not want to download directly, a set of disks made with Windows 98 Backup is available from the secretary in ISP. If you have access to the School of Business network, the files are available in T:\Users\Seagle\Public, and may be executed directly from the server. Be sure, however, to extract the working files to the hard disk on your machine.

POET uses OQL, the Object Database Management Group's standard object query language. It is much like SQL. To try it, you need to open the POET Developer's Workbench. Do this by executing the file "poet50\Bin\POETDev". From its file menu you can open a database.

Several example databases are included with the JAVA SDK. A fun one is the file "poet50\Examples\JavaODMG\TOONS\toonbase". This is a database of cartoon movies, studios, directors, and characters.

The menu OQL has a new query choice , and gives you a window to write and test queries. I illustrated a simple query:

SELECT *

FROM CartoonExtent AS cartoon

WHERE cartoon.year == 1966

And got a list of all films that qualified.

To get a quick summary of the kinds of data in the database, choose Classes and then Browse from the menu. A class diagram appears on the left, and members of the classes can be viewed on the right hand panel by clicking the class on the left.

Objects in this example are all pure JAVA objects saved by a JAVA program. The class definitions and other code are given in .java files stored in the same directory as the database.

A complete manual for the JDK is in file "poet50\JavaODMG\JavaProgGuide.pdf" in Adobe Acrobat format. Pages 199-224 of that manual describe the entire OQL language as implemented in POET, and show you how to use it in the POET Developer's Workbench. These pages are being put on reserve in the Draper library.