May 1997: we don't use msql any longer, so the applet won't work. I didn't touch these pages and the code since May, 96, and I'm also not going to care about it in the future. This applet is PAST.
However, I have a student working on a bigger Java-project that I created as a joined project of the company I work for (debis, Daimler Benz Interservices) and the University of Chemnitz, CS department, which shall help managing the debis sfi Intranet. It's in its final stage, uses a central SQL database (JDBC access) and looks promising.
Unfortunately, I can't show you most of my projects since they're only visible on debis' Intranet...(or they are for this Intranet, for which I'm the top-admin [until I have found a job in the US, it connects >600 employees in 7 locations all over Germany and is connected to the central debis Intranet)
CSN Database Access with a Java-Applet.
New Version May 29, 1996
It's not very useful since there are hardly any secrets on this server, but we do have an encrypting server (Apache-SSL); this document
The Applet consists of 10 class-files (together 45K) that have to be loaded by your browser. In addition, remember that this host is in Germany (Linux 386/8MB), so you should not be too impatient.
Note: When the db-server process is busy your connection request and all subsequent requests will be put in a queue and get processed in line. When somebody else is doing a complicated request or when there are lots of requests you have to wait a while. However, since all database operations are done in a separate thread you will be able to play with the window and to exit.
Some people get a 'couldn't find class dbWindow'-error. Today (08/23/96) I had this error myself, I solved the problem by reloading everything. It must be Netscape's fault since the Web-Server was not contacted after the starter class 'AppletButton.class' had been loaded (I looked at the log-files).
Here are screenshots. The Unix-version .gif's look like Win95, because my window manager at work is fvwm2-95.
New features: multithreaded, sorted output, changed the underlying database definition
You can tell me if the applet worked.
UPDATE (08/12/96): Meanwhile I got some responses, most of them positive, so I received mail from Hawaii and from Minneapolis yesterday (June 1996) telling me that 'it took less than a couple of seconds to do a sort', and that the 'application worked great, with adequate speed, and returned timely results'.
(11/26/96): Please DON'T ask me to write code for you or for general information on Java. I've really got better things to do than seeking information for you that you could find yourself, if you tried!!! (I get such requests every other week).
A Short Intro
There seem to be bugs in the Windows95 implementation of Java that make this applet almost unusable. The layout is not correct and the colors don't work; the buttons that you use for selecting output fields should have a red text when selected, which works fine with the Unix-versions of Java, but not with Windows95, where nothing happens.
I just discovered another Java-bug in Windows: I clear the lines in the result window before new results are displayed, but this does not have any effect in the Windows Java version, which is clearly not my fault.
UPDATE (08/12/96): Netscape Beta6 for Win95 displays my applet correctly which proves that it wasnīt my fault, good to know that. However, colors still donīt work.
Leaving all text fields blank returns ALL lines in that table. Many people try queries for items that don't exist, which is kind of senseless, so try this first.
Please don't ignore the informative messages in the status bar at the top of the applet window.
I allowed selecting more than one table simultaneously (JOINs). Since this causes considerable load on our server I introduced some serious restrictions in order to reduce the load; read about it some lines below.
This is the restricted Version of a database frontend applet for the CSN-Database. Some functionality has been removed in this version:
- When more than one table is queried you must provide a hostname in all of them which must not contain any meta-characters (% or _)! You can, however, use them in the other fields.).
- You can't write into the database
- Some fields aren`t accessible
You don't need to close the result window after each query, new reults are placed in that one window, after clearing the lines.
The following meta-characters may be used in the text fields:
- '%' matches any 0 or more characters
- '\' escapes ('_','%','\')
- '_' matches any single character
- all other characters match themselves
Use the two button rows to select the output fields (SELECT 'active buttons' FROM...).
Use the button 'Sort By:' to select a field (one for each table is possible) for sorted output.
The most important button in the result window is 'Use Line' which writes the fields of the selected line into the query window where you can continue to work with them.
When you start Netscape with the otion '-install' applets don't get many colors. In this case the database-applet looks terrible, you have been warned.
The program window is resizable (in X), although I disabled resizing. Looks pretty stupid if you try it though.
The program can run as a standalone program, without recompiling the source. All you need are the class-files.
You want the sources? No problem, here they are (21K, last updated June 10, 1996). These are the sources of the FULL version, not of the restricted one you're using right now. A (very small) sample of the database is included, since the applet only works on this one. You'll also need mSQL if you don't have it already.
Michael Hasenstein, 5. April 1996, last Update June 04, 1996