How do I connect an SQL mdf file to C# console app?

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I tried to connect a C# console app to a .mdf database file, both created using MS tutorials as listed below.
The console window is blank and when I stop debugging I get an error msg as below.

What I have tried:

I created a database (Pubs) with a single table (Authors) in Visual Studio in a Forms project. All looks good. I created this database and table to match the Microsoft exercise in
https://support.microsoft.com/en-us/help/314145/how-to-populate-a-dataset-object-from-a-database-by-using-visual-c-net
I created a new C# Console app and copied and pasted the code from the above MS article.
I copied the 2 files Authors.mdf and Authors_log.ldf I created earlier into the same folder where Program.cs is located.
As no password or user id had been setup when creating the database, I tried the connection string with and without "Password=myPassword;User ID=myUserID;"
The code builds and stops with a blank cmd screen. I have to stop debugging, and then I see 10 lines informing me that various DLLs have loaded and the last line is
The program '[6096] ConsoleDBTest.exe' has exited with code -1 (0xffffffff).
I did get errors indicating the database file could not be found, and those have disappeared, so I thought I could assume that it wasn't a matter of file location.
Any suggestions as I have to do something with this tomorrow morning (Australian time).

Posted 9-May-18 5:15am

jcarbuncles

Updated 14-May-18 2:19am

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[no name] 9-May-18 11:19am

We'd need to see your source code - first guess would be that the path to the .mdf file isn't correct.

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OriginalGriff · Answer 1 · 2018-05-09T05:30:00

OK, loads of problems here.

First off, your database should not be in the source code folder - at worst, it should be in the Bin/Debug and / or Bin/Release folder so it is easier to find - or better still in a data specific folder. This may help: Where should I store my data?[^]

Secondly, to use it from your own folder (even in a data folder) is a fairly poor idea - it means that your connection string needs to ATTACH the database so that SQL can use it, and that is only available for development, in the SQL Server Express editions - it isn't possible in production versions of the server software. You should pass control of the DB to SQL Server (easiest way: create it in SQL Server Management Console) and let it worry about where to keep it!

THen you need an SQL Server connection string, and that needs authentication, which for a local server may be pretty simple, or you may need an SQL User ID and Password combination to connect. This may help: Simple SQL Connection String Creation[^]

Once you have sorted that out, if it still doesn't work, show us the relevant code fragments and explain what happened.

jcarbuncles · Answer 2 · 2018-05-14T02:20:00

Solution 2

Thanks to those who replied to my question. You made me think about what I was doing, that I needed to attach the database to the project, etc.
End result was that it all worked fine, and I have learned quite a lot as a consequence.

Posted 14-May-18 2:20am