Cannot attach the file *.mdf as database

Question

Basically I\'ve followed a tutorial and decided to delete the .mdf file afterwards.

Now whenever I try to run the application I get the following error

Answer 1

Recreate your database. Do not delete it and your app should continue to work.

Answer 2

If you happen to apply migrations already this may fix it.

Go to your Web.config and update your connection string based on your migration files.

Data Source=(LocalDb)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\aspnet-GigHub-201802102244201.mdf;Initial Catalog=aspnet-GigHub-201802102244201;

The datestrings should match the first numbers on your Migrations.

Answer 3

Remove this line from the connection string that should do it ;) "AttachDbFilename=|DataDirectory|whateverurdatabasenameis-xxxxxxxxxx.mdf"

Answer 4

1. From Package Manager Console run:

   sqllocaldb.exe stop v11.0

   sqllocaldb.exe delete v11.0

2. Run your project

3. Register a user

Answer 5

You already have an old copy of that database installed in Server Explorer. So its a simple naming collision in the Server Object Explorer / SQL server. You likely created the same database Catalog Name already before you decided to move it to the Apps_Data folder. So that Database name already exists and just needs to be deleted.

Just go into Visual Studio > View > SQL Server Object Explorer and delete the old database name and its connection. Retry your app again and it should install the .mdf file in App_Data and create the same exact database again in the Server Explorer.

Answer 6

I think that for SQL Server Local Db you shouldn't use the Initial Catalog property. I suggest to use:

<add name="DefaultConnection" 
     connectionString="Data Source=(LocalDb)\v11.0;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\OdeToFoodDb.mdf" 
     providerName="System.Data.SqlClient" />

I think that local db doesn't support multiple database on the same mdf file so specify an initial catalog is not supported (or not well supported and I have some strange errors).