Why is EF4 trying to re-create my database even though the model hasn't changed?

Question

I have an ASP.NET MVC 3 Beta website using SQL Server CE 4.0. With both ScottGu's NerdDinner example and my own code, I will sometimes get the following exception as soon as I try to access the database:

File already exists. Try using a different database name. 
[ File name = D:\Sourcecode\NerdDinner\NerdDinner\App_Data\NerdDinners.sdf ]

Line 17:         public ActionResult Index()
Line 18:         {
Line 19:             var dinners = from d in nerdDinners.Dinners
Line 20:                           where d.EventDate > DateTime.Now
Line 21:                           select d;

[SqlCeException (0x80004005): File already exists. Try using a different database name. [ File name = D:\Sourcecode\NerdDinner\NerdDinner\App_Data\NerdDinners.sdf ]]
   System.Data.SqlServerCe.SqlCeEngine.ProcessResults(IntPtr pError, Int32 hr) +92
   System.Data.SqlServerCe.SqlCeEngine.CreateDatabase() +1584
   System.Data.SqlServerCe.SqlCeProviderServices.DbCreateDatabase(DbConnection connection, Nullable`1 timeOut, StoreItemCollection storeItemCollection) +287
   System.Data.Objects.ObjectContext.CreateDatabase() +84
   System.Data.Entity.Internal.DatabaseOperations.Create(ObjectContext objectContext) +35
   System.Data.Entity.Infrastructure.Database.Create() +70
   System.Data.Entity.Infrastructure.CreateDatabaseOnlyIfNotExists`1.InitializeDatabase(TContext context) +360
   System.Data.Entity.Infrastructure.Database.Initialize() +272
   System.Data.Entity.Internal.InternalContext.Initialize() +90
   System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) +34
   System.Data.Entity.Internal.Linq.EfInternalQuery`1.Initialize() +140
   System.Data.Entity.Internal.Linq.EfInternalQuery`1.get_Provider() +29
   System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider() +34
   System.Linq.Queryable.Where(IQueryable`1 source, Expression`1 predicate) +63
   NerdDinner.Controllers.HomeController.Index() in D:\Sourcecode\NerdDinner\NerdDinner\Controllers\HomeController.cs:19

I cannot figure out why this works sometimes with an existing .dbf file and other times it complains. I have even tried explicitly setting the default behaviour with

Database.SetInitializer(new CreateDatabaseOnlyIfNotExists<...>());

Has anyone else experienced this?

Restarting Cassini doesn't seem to make a difference.
Hitting refresh in IE after receiving this error will make the exact same page load properly.

From your stacktrace: `CreateDatabaseOnlyIfNotExists`. The EF is *trying* to do the right thing. But somehow the check to see if the DB exists failed. Look into that. — Craig Stuntz, Oct 07 '10 at 17:41
Here's the weird thing. Loading the .NET framework symbols/code and debugging the code actually stops the problem from happening. Every time. I don't get it. — Jedidja, Oct 07 '10 at 18:44

score 8 · Answer 1 · edited Apr 03 '11 at 15:10

Sorry to resurrect such an old question, but I was experiencing this today and have found a workaround which does not involve installing an older version of the CTP.

From The correct url for the blogpost is http://www.hanselman.com/blog/PDC10BuildingABlogWithMicrosoftUnnamedPackageOfWebLove.aspx (about half-way through the blog post)

*Go into your AppStart_SQLCEEntityFramework.cs file and the DefaultConnectionFactory line to this:*

Database.DefaultConnectionFactory = new SqlCeConnectionFactory( 
    "System.Data.SqlServerCe.4.0", 
    HostingEnvironment.MapPath("~/App_Data/"),"");

My particular database is placed in the App_Data folder but I'm assuming that if yours is not you should be able to change the path to suit and it will work.

Hope this helps!

Brilliant, that helped me out anyway. – Johan Danforth Jan 14 '11 at 14:47 — Johan Danforth, Jan 14 '11 at 14:47
Just did this today with newly release 4.1 of EF... :-) – Kevin LaBranche Mar 18 '11 at 19:15 — Kevin LaBranche, Mar 18 '11 at 19:15

score 3 · Answer 2 · answered Oct 15 '10 at 22:09

3

It looks like this is a recently discovered bug. MSDN Forum

The workaround is to re-install SQL Server CE 4.0 CTP 1 download

answered Oct 15 '10 at 22:09

Dave

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score 1 · Accepted Answer · answered Oct 12 '10 at 10:44

1

Install and use SQL Server CE CTP1, which is still downloadable on Microsoft sites. This solved my problem with that.

answered Oct 12 '10 at 10:44

zigomir

985
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score 1 · Answer 4 · answered Feb 25 '11 at 21:36

I had the same problem today with released MVC3 and SQL Server CE 4.0 downloaded with NuGet and it was resolved by uncommenting the line:

    DbDatabase.SetInitializer(new CreateCeDatabaseIfNotExists<MyContext>());

And replacing MyContext with the context class that was inheriting from DBContext in the models folder.

score 0 · Answer 5 · answered Apr 03 '11 at 15:13

0

The final SQL Compact Edition 4.0 is out and after installing it the issue is not happening anymore. Here is the announcement from the team blog:

Microsoft SQL Server Compact 4.0 is available for download

answered Apr 03 '11 at 15:13

gyurisc

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Why is EF4 trying to re-create my database even though the model hasn't changed?

5 Answers5