Question

I’m a bit confused about Entity framework, I would like to use code-first approach; infact I would like to write how my database tables are composed through class definition.

The main problem is that I need to create a database (or open it) by choosing dinamically it’s path (the user can choose what database to open and can create new one when he wants). I’ve chosen Sql server compact to achieve this, however I still don’t understand how to use code-first approach for this situation because I don’t understand how to choose where database should be created with code-first approach, if is possible.

Can anyone explain what I’m doing wrong and suggest a different route, if any? Thanks

Answer 1

I just had the same problem a few days ago. Here’s how I got it to work:

In your application startup code add the following:

using System.Data.Entity.Database;

// ...

DbDatabase.SetInitializer(new MyDbInitializer());
DbDatabase.DefaultConnectionFactory = new SqlCeConnectionFactory(
    "System.Data.SqlServerCe.4.0", 
    @"C:\Path\To\", 
    @"Data Source=C:\Path\To\DbFile.sdf");

The Initializer should look something like this:

using System.Data.Entity.Database;

public class MyDbInitializer : CreateDatabaseIfNotExists<MyDbContext>
{
    protected override void Seed(MyDbContext context)
    {
        // create some sample data
    }
}

If the CreateDatabaseIfNotExists is not the thing you want, there are more kinds of initializers you can use, or you can also create your own. More information on that can be found here:

http://blog.oneunicorn.com/2011/03/31/configuring-database-initializers-in-a-config-file/

Hope this helps.