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

StackOverflow https://stackoverflow.com/questions/3882963

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.
Was it helpful?

Solution

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

OTHER TIPS

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!

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

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.

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

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