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Java as Front-end to VFP
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De
07/10/1999 02:00:05
 
 
À
07/10/1999 00:54:15
Information générale
Forum:
Visual FoxPro
Catégorie:
Client/serveur
Divers
Thread ID:
00273535
Message ID:
00273549
Vues:
28
>>I'm inviting Paul Vlad Tatavu to tell us a little more about his experinces in using Java as a front-end.
>
>BTW, you can address a new message to someone in particular here on UT. This way, you can be sure that that person will see your message in his/her replies box.

I couldn't remember how to do that and decided it was a PUTM feature. Where is it?


>Otherwise, none of our clients will use Access database. But it's also good for demos, when you don't want to install Oracle or SQL Server on the demo laptop.

Over the last year I wrote an Access app for a C++ developer. It has serious memory-leaks under Win 95/98 but seems stable under NT. Both of us would fight hard to avoid Access in the future.

Of course Access as a Rapid Development Tool is separate from Access/Jet as a back-end database. What are the things your clients don't like about the Access database?


>So, the middleware is done almost 100% in VC++ with ATL and ADO (some VB COM objects, too, unfortunately:)).
>
>Now, from Java UI/client point of view, it really doesn't matter which is the developemnt tool for the middleware or server side.

Could you imagine using VFP as middleware in this type of situation?


>>3) How does the form handling/presentation speed compare to VFP?
>
>Just to be clear: I consider Java ONLY for web applications. For any other (standalone/desktop/LAN) type of app, choose any other developement tool.

Please be more specific here. What I have done in VFP 5.0 is develop a traditional file-server oriented timeshare reservation and billing system. There are typically between 20 and 40 users and the system is reasonably stable at this point. But I realize that my next development effort should be client/server. It should not be possible for a workstation to corrupt the main database, no matter what goes wrong at the client-end, and that possibility is unavoidable as long as the actual database updating is done at each client's machine.

So assuming a lan-based client-server solution, what would be your choice of development tool at each level:

Back-end database ?
Middleware ?
Front-end ?


>About form speed in VFP: I think Jim Booth said it best: a well designed/developed VFP app will have forms that are fast enough for any user. These are not exactly his words, but... From my experience: Almost any slow VFP form can be modified to perform well even on average computers. I optimized some VFP forms (2 years ago) and obtained a performance increase of 23 times!

Hearing more about that would make an intersting thread...



>Finally, it took about 1.5 seconds to load the slowest form. It's also true that, sometimes, due to poor database design, compatibility with legacy apps, etc, this may not be possible.

I'm using Visual FoxExpress and apparently form-load speed is not one of it strong points. (Haven't tried the new 6.0 version yet.) I get acceptable speed (1-3 second range) by keeping all of my main forms open. One hides behind another.

The app I replaced was written in DataFlex for DOS and one thing you can say is that the forms appeared instantly. It bothers me that with all the hardware speed we have now, that in many cases the user sees an app which is much less responsive than the old DOS apps. I really think this is unexcusable. I mean the hardware is 10-100 times faster than a few years ago. Why should the form-handling be 10 times slower?

Peter
Peter Robinson ** Rodes Design ** Virginia
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