Note: This blog post relates to a library undergoing development and as such the information is likely to become outdated.

Even with Database First through the EDMX gone in Entity Framework 7 it's still possible to work with existing databases.

While trying this out with one of my databases I ran into the following Exception:

<Message>An error has occurred.</Message>

<ExceptionMessage>Invalid object name 'SomeClass'.</ExceptionMessage>

<ExceptionType>System.Data.SqlClient.SqlException</ExceptionType>

<StackTrace>
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)[...]
</StackTrace>

The Entity Framework "Invalid object name [class name]" exception means that the matching table for one of your classes hasn't been found.

In this case I'm trying to map the SomeClass to the underlying SQL table Map.Test:

[Table("Test", Schema="Map")]
public class SomeClass
{
    public int Id { get; set; }
}

The current version of EF7 (7.0.0-rc1-11953) does not have support for mapping using attributes in this way. Instead one must use Fluent configuration in the DbContext as follows:

public class MyContext : DbContext
{
    public DbSet<SomeClass> SomeClasses { get; set; }

    protected override void OnConfiguring(DbContextOptions options)
    {
        options.UseSqlServer(ConnectionString);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.Entity<SomeClass>().ForRelational().Table(tableName: "Test", schemaName: "Map");
    }
}

The mapping is configured fluently in the OnModelCreating method. For slightly more useful information about setting EF7 up see this link.

I hope this helps!