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Applets and Databases

Posted on 1998-07-07
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Last Modified: 2010-03-30
I have created a small Applet which uses JDBC/ODBC to allow the user to interrogate a database and change the values. The Applet works perfectly in the Applet viewer but if I try to run the Applet in a browser then it does not work. I assume that the problem is something to do with security.

How can I make the Applet work in a Browser. I am sure that there must be a way to handle databases in this way.

many thanks for your assistance...

Richard H
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Question by:RICHARDH
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msmolyak earned 30 total points
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The questions to you are:
Where is your applet coming from (local disk or a Web server), where the JDBC driver is installed (on the machine where the applet is running or the machine where it is coming from) and what category driver this is (that is, is it a 100% Java driver which talks natively to the database or it is a JDBC/ODBC bridge which requires loading some DLLs)?

Also what error message are you getting?

Depending on your answer we will conclude that either your applet is trying the go outside the security sandbox (and there are ways to allow applets to do that) or it can stay within a sandbox with minor tweaking.
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by:RICHARDH
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To: msmolyak,
Thanks very much for the prompt reply. I will try to answer the questions to the best of my knowledge.

1. The Applet has been produced using Lotus Bean machine and the driver is the one supplied with the package. I am not sure but I think that it is a JDBC/ODBC bridge.

2. At present, I am running the Applet on the same machine as the ODBC database in that I have published it to the Webserver which happens to be on the development machine. However I am looking at the Applet through a browser pointing to the page stored on the Web Server.

3. I do not get an error, it is simply that the data does not appear in the fields as it does when viewed as an applet, not through the browser.

I hope that this provides enough information for further comments. I am going on vacation early tomorrow so I may not pick up your repl;y for a weeks or so.

Many thanks for your help, it is much appreciated.

Richard.H
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by:msmolyak
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Both IE 4 and Navigator 4 have Java consoles. Did you check those for error messages? If you indeed do not get any, could you put some print statements in your program to see where the browser behavior is different of that of the appletviewer.

Make sure you can register the driver and instantiate it.
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by:RICHARDH
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The problem with Lotus Bean machine is that you do not get a great deal of control over the script.

How do I go about testing to see if I can register and instantiate the driver.

thanks
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by:msmolyak
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Can you execute your applet in one of teh abovementioned browsers? If so, simply put System.out.println("...") statements to see where the program gets stuck.
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