Tag Archives: MSSQL

Cannot attach the file ‘C:…database.mdf’ as database x – Entity Framework

Hi everyone,

I ran into the following error when attempting to run ‘update-database’ on an initial migration:

Cannot attach the file ‘C:Users…App_Dataaspnet-…115933.mdf’ as database ‘aspnet-…15933’

The solution to this one is pretty easy, remove the initial catalog property from your connection string.

…33.mdf;Initial Catalog=aspnet…

This is apparently caused by issues with EntityFramework and multiple projects in the same database. See the following stackoverflow answer for more info: https://stackoverflow.com/a/20176660/522859

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View Generated SQL in Entity Framework (EF)

Hey everyone,

Just a quick post on how to view the generated sql in entity framework. To start with, just add the following line to your db context constructor:

public class TestDbContext : DbContext
    {
        public TestDbContext() : base("name=TestDbContext")
        {
            this.Database.Log = s => System.Diagnostics.Debug.WriteLine(s); //This line
        }
        ...

With this line added, you should now be able to see all of your generated sql in the output window.

SELECT TOP (1) 
    [Project1].[VidId] AS [VidId], 
    [Project1].[CreatedAt] AS [CreatedAt], 
    [Project1].[Check] AS [Check], 
    [Project1].[SourceCheck] AS [SourceCheck]
    FROM ( SELECT 
        [Extent1].[VidId] AS [VidId], 
        [Extent1].[CreatedAt] AS [CreatedAt], 
        [Extent1].[Check] AS [Check], 
        [Extent1].[SourceCheck] AS [SourceCheck]
        FROM [dbo].[Vids] AS [Extent1]
        WHERE [Extent1].[VidId] < @p__linq__0
    )  AS [Project1]
    ORDER BY [Project1].[VidId] DESC

-- p__linq__0: '535' (Type = Int32)
-- Executing at 28/06/2014 5:00:16 PM +10:00
-- Completed in 0 ms with result: SqlDataReader

If you’re not using EF6, there were a few other options where I came across this solution: http://stackoverflow.com/a/20751723/522859