Multiuser Applications 4

[dyarwood]

Hi

I am trying to create an ordering system using VB.NET and as the customer is not got internet access they are unable to use an ASP.NET website. I am therefore trying to create a Multiuser (500 approx) application with an Access database. A few questions would a VB.NET windows app cope with similtaneous user access and would the Access db be able to handle the load.

Thank you for all replies.

dyarwood

 

[dyarwood]

Forgot to add that I would prefer to have a single front end executable on a server.

 

[chiph]

500 users on Access? Not a chance. You'll need SQL Server, Oracle, or DB2 for something like that.

Chip H.


____________________________________________________________________
If you want to get the best response to a question, please read FAQ222-2244 first

 

[dyarwood]

Chiph

I will try for the SQL Server angle but might have to go down MySQL. Would a single front end be able to cope?
Would a MySQL db cope with that volume?

 

[chiph]

MySQL can handle it.

You need to make some decisions soon about how to handle concurrency & other typical multi-user issues.

I would suggest you buy a copy of Martin Fowler's Patterns of Enterprise Application Architecture:

http://www.amazon.com/exec/obidos/A...69616/sr=ka-1/ref=pd_ka_1/103-4909916-5085435

It's a little Java-centric, but all the discussions in there are equally valid for .NET.

Chip H.


____________________________________________________________________
If you want to get the best response to a question, please read FAQ222-2244 first

 

[chrissie1]

and I don't see any reason that you can't use ASP.net. You just need to install a webserver like IIS. on one of the servers.

Christiaan Baes
Belgium

If you want to get an answer read this FAQ faq796-2540
There's no such thing as a winnable war - Sting

 

[dyarwood]

The customer does not have access to the internet. Would the webserver not need access to the internet?

 

[chrissie1]

Nope

Christiaan Baes
Belgium

If you want to get an answer read this FAQ faq796-2540
There's no such thing as a winnable war - Sting

 

[dyarwood]

Quite interested in that solution. I was assuming that as there would not be internet access at all an ASP.Net solution would be out of the question. Will have to investigate that.

Still open to suggestions.

 

[RiverGuy]

What it seems like you wish to do is allow the users to run an executable on a network share? Why not just have the application installed?

It seems like you have 4 choices:

1. Install the whole app
2. Create it in ASP.Net, and use an intranet (don't need internet access).
3. Create a light-weight app and use webservices as a middle tier to communicate to the database (may not turn out to be much lighter, depending on what you are doing)
4. Have the users' shortcut point to an executable on a network share.

I would choose option 4 lastly.

If you do choose option 4, well, the users would need the .Net framework and MDAC installed at least.....so you're looking at installations anyways.

 

[chrissie1]

personnaly I prefer option 1, because asp.net has some restrictions. Number 1 is called "Rich Client" and there is a reason for that.

Christiaan Baes
Belgium

If you want to get an answer read this FAQ faq796-2540
There's no such thing as a winnable war - Sting

 

[dyarwood]

Think your right with the options. Unfortunately there is no intranet only a network drive that they access. So looking at 1 or 4 and possibly 3.

 

[RiverGuy]

Christiaan,
I think I was typing my answer as you typed yours. I didn't need to repeat the ASP.Net option then. Sorry about that.

dyarwood,
To be able to do option 3, you would also be able to do option 2. ASP.Net and Web Services both use IIS. This is installed on a server. It's part of Windows 2000, or Windows XP, or Windows 2003 Server. It may not be installed on your server, but its on the installation CD.

To use IIS, you don't need internet. If your clients can see the IIS server, then they would be able to get to it like:

http://YourServerName/YourApplication.

It looks like a Web URL, but its pointing internally.

What is the main reason you want to use the same executable from a network share? Perhaps we may help you with more ideas.

 

[chrissie1]

Riverguy, youre my Hero and don't need to apolagize for anything.

BTW Dyarwood I would do a lot of reading and testing before you implement your app. It seems to me that you still need a lot to learn. And an app that has 500 users will have 500 people that can complain. Just a thought.

Christiaan Baes
Belgium

If you want to get an answer read this FAQ faq796-2540
There's no such thing as a winnable war - Sting

 

[RiverGuy]

Good point. 500 people who can complain means that it could be a headache to implement changes without developing something elaborate. This is where ASP.Net shines. If there is a glitch, you just correct it at one place, and the next time the user visits the site, the changes are in place.

With any kind of client residing on the user's machine, you either have to have some patching scheme in place, or do a complete re-install.

If you have a shared .exe, well I suppose that would work without patching, unless you need to implement something new in which the client needed to install drivers for.

 

[chrissie1]

I have a question about the shared exe. If you want to update that do all users need to be disconnected?

Christiaan Baes
Belgium

If you want to get an answer read this FAQ faq796-2540
There's no such thing as a winnable war - Sting

 

[RiverGuy]

I don't know. I'm sure Chip may know, but I'm not as savvy for Windows domain/Sys admin as programming. I would think that it wouldn't let you do this while users had it open, so a way to overcome this would be to disconnect users sometime in the middle of the night when its not being used (if that is ever the case), and then replace it.

 

[dyarwood]

chrissie1

You are right I do have a lot to learn as only been in this game for 6 months. Only really done apps for a single pc. i'm trying to get round the problem (without massive amounts of support as an after effect) for the no internet and no intranet.

A single shared exe was an idea but obviously needs more thought. Just needed some feedback as I've been searching the web but not found an much.

Thanks for all your advice.

Back to the drawing board.

 

[chiph]

Running an EXE off a network share has it's problems. Like RiverGuy pointed out, everyone would have to have the .NET framework installed, so you don't get away from doing client installs (a huge pain).

Updating the EXE on the network drive can be difficult if someone has it open. Usually what you end up doing is unsharing the folder (breaking everyones connection), replacing it, then re-sharing. There will always be that one person who had unsaved work, who lost it when you broke the share.

Don't forget that running a shared EXE also requires the .NET permissions to be set to allow it. You either allow stuff to run from the Intranet Zone (not recommended), or grant permission explicitly to the EXE. Code signing could help here.

If it were my application, I would go the ASP.NET route. Doing so will allow people to run remotely (via VPN or dial-up) with minimal performance penalty. 500 users for a web server isn't any big deal if the app is written correctly. If the company hires another 500 people you can add a 2nd web server along with a hardware load-balancer.

Using a load-balancer gives you another benefit -- if your server goes down it will route all your requests to the 2nd (or 3rd or 4th) server automatically.

Chip H.


____________________________________________________________________
If you want to get the best response to a question, please read FAQ222-2244 first

 

[dyarwood]

ASP.NET route i agree would have been my first point of call (multi-user interface begs a web page) but no intranet no internet access causes problems. Also I know they would not want to start implementing a web server.

Going back to the original idea of using an Excel Template file with VBA coding. Simple and doesn't need a back end or .NET framework. Updates will still be a bit of a pain but the network drive is remapped each night so the connection is broken at some point.