Question

I deployed a simple ASP.net MVC application on IIS (7.5 under win 2k8 R2 64 bit), and it created its databases (ApplicationData and the second one with my own data) when I started using the app.
The databases (.mdf and .ldf files) were created inside App_Data folder.

Application uses entity framework code first approach. I had to change the app pool’s identity to Network Service to get the webpage working. I also had to manually create this App_Data directory and assign permissions for Network Service user to modify it’s contents.

Now the problem I got is that I can’t see those databases in Management Studio (got SQL server 2012 express with advanced services installed). I can attach them manually if not using the webpage for a longer time, otherwise the .mdf files are locked by sqlservr.exe process of Network Service user.
All the time I got two simultaneously running sqlservr processes. One is run by MSSQLsomething user and the second one by Network Service. However, I got only one instance of SQL server installed (I’m 100% sure of it).

Could anyone explain me how is that possible that Management Studio cannot see those databases even at the moment they’re being used (locked by sqlservr.exe process)?

Answer 1

This is because the database is hosted in User Instance Mode, and therefore not actually attached to the ‘official’ database server.

In that article you’ll see that this is enabled using User Instance=true; in the connection string. To switch it off you specify User Instance=false;.