I am working on an app in VS which includes a SQL database stored locally on my C drive. I can publish the app and it works fine on my own computer, but because the database is stored locally, I cannot run the app from any other computer (SQL exception 52). I would like to move the app to a network drive so it can be accessed by multiple users.
I have tried to move the database by changing the default database location in the SQL server object explorer. I’m wondering if I should have SQL server express LocalDB installed?
I have no programming training but have been dumped with this project at work as I have used VBA before, so I’m sorry if this question it stupid. I would really appreciate it if someone could point me in the right direction!
When accessing your database, rather than using just the database name, you should specify the filepath aswell, like this:
Public Filename As String = $"[**FilePath**]ActiveFitness.accdb"
This tells the programme where to look for the database, and is better practice than relying on the default location.
Related
I am trying to find the best procedure to get data from our SQL server at headquarters to update apps running on local machines in various locations not connected to our network. Our current data and application is in Foxpro where you simply copied the data file, so I am not very familiar with using SQL databases.
The field app uses localdb and users don't save anything to the database. When the app opens it checks a web site to for updates. I tried detaching our HQ .mdf and .ldf, downloading it and overwriting it on the local machine, but localdb would not attach to the new file (same name). I thought localdb closes and detaches when the application closes , but maybe I am wrong. I also wonder if I need the log file since no changes are made and I dont need to rollback anything. I have searched for a good article on this topic but haven't found anything. This must be a fairly common scenario in many companies.
You want to look into using replication, probably snapshot replication. This allows you to distribute on whatever schedule is applicable to send one or more tables, or other objects, to off site sql server instances. You can use Http to send data.
I'm fairly newb when it comes to programming and even newer when it comes to database management and integration.
So I have a VB.NET Windows Application that uses a SQL Database. I use LINQ to SQL to fill datagridviews in windows that show table data and also use LINQ to SQL to save data to the database.
All works wonderfully however...
When I publish the application, the database isn't external as far as I can tell. It seems to build itself into the application so once the application is installed, the database is there, it views and saves data, but if the computer crashes or the application is uninstalled, all that data is going to be lost without a way to back it up.
I'm using Visual Studio 2010 Express. I created the SQL Database in VS2010-Exp as well. I feel like there's something simple I'm missing here. When the application gets published and then installed, where is the physical database going?
Thanks!
It is running as part of the application. If you wanted a separate, central database, you would need to have an instance of SQL server running in some accessible location.
I am busy developing my own application, it uses a sql server database and it is connected through an entity framework. I use store procedures to insert, update, delete, select from my database.
The app works perfect on my machine even when I publish it. But my problem comes in when I try to install the app to my friend’s computer. It crashes and does not start because it cannot connect to the database.
Is there a way to publish my app with the database, without importing all the tables, store procedures and database into my friend’s pc? I just want to make it so the user just has to install the app and it works.
Your app relies on the db to work, so if you want to put it on your friends PC then you need to make the DB available somewhere, whether it be a local copy or a copy stored on a server somewhere running SQL.
How are you storing your connection string? Is it hard coded in the app or are you utilising the app.config file? To do what you're trying to do you'll need to put the connection string into the app.config file, so you can change it depending on the installation.
either that or
if you want to run your app without data, put a demo flag or something into the app.config file. Put some code into your app to check this value, if it's true then bypass the SQL code and maybe supply some demo data which is hard coded.
Does this make sense?
You could use SQL CE, but you may find it a little more difficult to 'design' your database in it if you are more used to working in SQL Server.
Have you considered SQL Server Express as an option?
On the connection string issue, you can now get the data connection wizard that Microsoft use in Visual Studio via Nuget; this makes adding a way to dynamically configure connection strings on your clients machine much easier.
Lastly, connection strings for the entity framework are different from standard SQL connection strings. Make sure that you clearly understand the differences before you start trying to configure them programmatically. Julie Lerman's excellent book on the Entity Framework explains the differences well.
I'm doing a project with vb.net (smart device) on visual studio 2008 and I need to connect to a database on the device itself (I do not have a physical device to test, only emulation). How should I go about doing it? I would like the database to be in the device on start up.
I've read on the internet that you have to make a reference to System.Data.SqlServerCe but the documents are, in my opinion, vague. So, I'm pretty lost here.
So there are two questions here:
How do I deploy my database so it's there when my app starts?
How do I access that database from my app?
Both are straightforward.
A1. You have a couple options. First, understand that SQLCE databases are a single file, typically with an SDF extension. You can either package it with your app for deployment, so you know it will be there on first run, or your app can check for its existence on startup and crete the file if it's not there. If you need to populate the initial database with data (lookups, etc) then option 1 is probably better. As long as you deploy/crete the database in a persistent storage location (and under WinMo/Pocket PC that's pretty much anywhere), it will always be there when your app starts up.
A2 You are correct that you need to add a reference to System.Data.SqlServerCe, which is again straightforward. Just add a reference in your smart device project:
Once you've done that, you use the SqlServerCe namespace objects to create the database, tables, indexes, etc, insert and query data, and all of that good stuff. Tutorials 2 and 3 on MSDN here are a really good start and they have VB.NET examples. The nice thing is that most desktop examples for VB.NET accessing a SQLCE database will work as-is on the device, and the things that don't work are usually in the presentation of the data, not the actual database access code itself.
I'm writing a desktop application that uses the main access database that will be hosted on a central server, but there will be a laptop with the app on that has an offline mode so records can be created offsite. When the laptop returns I want it needs to be synced back to the main database.
Has anybody got any pointers on a way to do this, I've briefly read about JRO but is there an alternative / better method?
Originally, I was just going to write some custom code to do this, but thought I'd check to make sure there wasn't something already out there.
Jet Replication is a perfect solution for this kind of scenario, because you can use the simplest form of it, Direct Replication, and don't need to have any outside dependencies.
Assuming your server is named \HomeOffice\ and the database is named "MainDatabase.mdb" and is stored in the \AccessDatabases\ folder, you could use this code behind a command button to synchronize from the laptop to the server:
Dim dbServer as DAO.Database
Set dbServer = DBEngine.OpenDatabase("\\HomeOffice\AccessDatabases\MainDatabase.mdb")
dbServer.Synchronize CurrentDB.Name
dbServer.Close
Set dbServer = Nothing
Now, there's no error handling, and you haven't checked for conflicts, so you'd need to do more than that, but that would get you started with the basics.
See the Jet Replication Wiki for lots more information on Jet Replication.
Access (at least through 2003) has built in capabilities to replicate a database that would be far better to use than rolling your own.
Here's some documentation on that feature: Database Replication
MS Sync Framework could be the answer, but it's a bit tricky to set up... http://msdn.microsoft.com/en-us/sync/bb821992
There is the Microsoft Sync Framework that is compatible with ADO.NET and MS SQL Server / SQL Server Compact, but that's not a small component, more like a multi-component framework.