Alternatives to traditional database topology - sql

I've been working with visual studio in a corporate environment for a long time, where we have a central SQL Server set up to store the data for all our in-house programs.
I've been asked to work on a side job for a small company where they want a program that will share data from a database between a half dozen computers.
My first reflex is to get them to set up a small server, install a database and then connect to it like I usually do, but before I start I'm wondering if there is a better way to do it.
Part of my problem is that if this works out really well, there is a chance that the program could be used in other companies, and I don't want to have to set up a server and write a custom version with a custom connection string for each one.
It could be that I'm thinking to deeply about this, I'm just hoping that a little research ahead of time might save a lot of time down the road.

Why would you need a custom build just to change the connection string ?
Just change your app App.config - or are we missing something here ?
What is App.config in C#.NET? How to use it?

Related

Possibilities of Datazen server migration

I know that similar topics have been already raised, but maybe there are some latest news or ideas?
I want to migrate Datazen users/sources/dashboards etc. to another server (production one) in a smooth way. I was trying to do that via backup/restore, but then I couldn't access the control panel on the target server. I received an error
401 unauthorized access.
Maybe I should change something in logs/config files on the destination server?
Any ideas? I would be grateful for any help!
I dont think there is a way to do this out of the box. However, the files are quite simple XML, so can be pointed at a different server if you know PowerShell (and work out the correct values from the server).
You will have to re-point the GUID, ServerGUID and ServerURI within the sources.xml file and then rezip (as .datazen). Providing you have your hubs set up the same, Datazen will then believe the file belongs to your prod environment and you will be able to publish

Many user using one program (.exe) that includes datasets

I created a time recording program in vb.net with a sql-server as backend. User can send there time entries into the database (i used typed datasets functionality) and send different queries to get overviews over there working time.
My plan was to put that exe in a folder in our network and let the user make a link on their desktops. Every user writes into the same table but can only see his own entries so there is no possibility that two user manipulate the same dataset.
During my research i found a warning that "write contentions between the different users" can be occur. Is that so in my case?
Has anyone experience with "many user using the same exe" and where that is using datasets and could give me an advice whether it is working or what i should do instead?
SQL Server will handle all of your multi-user DB access concerns.
Multiple users accessing the same exe from a network location can work but it's kind of a hack. Let's say you wanted to update that exe with a few bug fixes. You would have to ensure that all users close the application before you could release the update. To answer you question though, the application will be isolated to each user running it. You won't have any contention issues when it comes to CRUD operations on the database due to the network deployment.
You might consider something other than a copy/paste style publishing of your application. Visual Studio has a few simple tools you can use to publish your application to a central location using ClickOnce deployment.
http://msdn.microsoft.com/en-us/library/31kztyey(v=vs.110).aspx
My solution was to add a simple shutdown-timer in the form, which alerts users to saving their data before the program close att 4 AM.
If i need to upgrade, i just replace the .exe on the network.
Ugly and dirty, yes... but worked like a charm for the past 2 years.
good luck!

Visual Basic / ASMX - how to use application cache variable?

I'm trying to amend our content management system so it'll handle SQL database failures more gracefully. It's a bunch of ASMX pages, and a Helpers.vb file in which I've written a SQL connection tester function.
Each of the ASMX pages call the same function.
I need to create a variable I can check that's persistent and performant, otherwise I'm going to have fall back on something disasterously slow like reading a text file every time I set up a sql connection string.
I've tried using application caching, but either it doesn't work in the context of my helpers.vb file, or I've made a mess of the syntax. One problem that's already stymied some of the approaches I've found via google - I can't use 'Import System.Web.Caching' - IntelliSense doesn't show the 'Caching' part.
Has anyone got any example code that might get me up and running? Or an alternative approach?
#Mike,
Many thanks, now I'm using HttpRuntime.Cache correctly... it works!
Thanks everyone for taking the time to post :)

Application Scope settings or something else

I am in the process of building a completely fresh version of an application that has been in existence for a good many years. I can look back with horror now at some of the things I had done, but the whole point of life is to learn as we go along. The nice thing now is that I have a clean slate from which to work, and it's because of that that I thought that I would seek some advice from you all.
User settings are great for those things that each individual user would naturally want to and ought to be able to change, a theme or visual style for example. Application settings should quite obviously apply to the entire application irrespective of whoever uses it.
Somewhere in the middle though are a set of settings that I would like to give the system administrator the opportunity to change (default work periods, appointment time slots, the currency the company wants to use as its main trading one etc etc). These can't be user settings because individual users should not be able to change them, nor should they be application settings because I as the developer have no idea what the end user (or to be more exact the senior end user) would want to set them to.
Many years ago I might have considered writing such settings to the registry, or an ini file. I could perhaps (as this is an application that is tightly integrated with its own custom database) create a one off settings table, and read in the relevant settings at program startup. I could perhaps opt for a separate 'universal settings' xml configuration file stored in the all users directory. Clearly a number of options.
What I would like to try and establish though is the most efficient way to approach this. What is the best trade off between file read and write operations as against reading everything into a set of public constants at application start-up? These are not going to be settings that will only be referred to occasionally so efficiency is going to be key.
Just so that there is no ambiguity as to what the application will be. Traditional winforms, using vs 2012 as the development ide and vb.net as the code base based on .net4.5 and ef 5.0. Backend data to be stored in either sql express or full sql server. Target operating system for end users will be windows 7 or above (so due respect for the uac will be required).
I'd welcome any suggestions that you might have.

Run application from documents instead of program files

I'm working on creating a self updating application and one issue I'm running into on Vista and Windows 7 is needing to have admin privileges in order to update the client. I've run into issues with clients that have their users running under restricted permissions and they would have to have IT log onto every machine that needed to update the client since the users were not able to.
A possible work around I'm considering is to have the launcher application installed into Program Files as normal, and having the real application that it updates installed in the users documents somewhere, so that they could update and run new versions without IT becoming involved.
I'm wondering what potential gotchas I'm missing here or what I should be aware of before heading down this path. I'm aware that click-once does something very similar, and I'd be using it, except I need the ability to do silent updates, without any user interaction.
This is how it is supposed to be. The last thing most IT departments want is a user randomly updating a piece of software. This could have all sorts of unintentional side effects such as incompatibility with the older version's files, new and possibly insecure functionality, etc. This is why IT departments disable Windows Update and do their updates manually in a controlled fashion.
If the users want an updated version of the software they should be requesting it from their IT department. Those computers and infrastructure don't belong to them, they're simply borrowing time on them from the company they work for so they can do their job.
Is there an issue with having only one installation of your program? Is it particularly large, for example?
Do you require admin privileges to run your program?
If not, odds are you don't need the Program Files folder.
I suggest you forgo installing to Program Files entirely and just install your program into the user's folder system at <userfolder>\AppData\ProgramName.
If you happen to be using .NET, look into the ClickOnce deployment mechanism. It's got a great self-updating feature that'd probably make your life a lot easier.
Edit: Just saw your last sentence. ClickOnce can force the user to update.
A couple of things:
If you decide to move your app to some place in documents, make sure that your application writes data transparently to where your program is installed, e.g. if there are hard coded paths anywhere in the code that are pointing to bad places. Perhaps this is not an issue for you, but might be something to keep in mind.
We solved this in pretty much the same way when we decided to implement a "live update" feature. But instead we installed a service which is running with administrator rights. This service in turn can run installers once the program needs to be updated. With this type of solution you don't even have to move your applicaton out of program files.
Cheers !
Edit:
Another neat thing with having a service running as administrator. Is that you could create a named pipe communication with it and have it do things for you, like you wouldn't be able to do as a normal user.
A loader stub is a good way to go. The only gotcha is when you have to update the loader; the same initial problem applies (though that should be pretty infrequent).
One problem that I can think of off the top of my head is that you're stepping outside the entire idea of keeping things more "secure." Since your executable exists in a location that should be completely accessible to a non-administrator, it's possible that something else could slam your exe thus subverting security.
You can probably leverage AppLocker. It may only be for Win7 though I'm not running Vista any more. ;)