title: From what information is EF4 Code first building the conceptual model
body: <p>As I understand Code First is building a model to work with EF4 in memory and where you can fine tune your mappings and stuff.</p>
  
  <p>Based on what information is this model being build?</p>
  
  <p>You see I have an existing application and am looking to change our DAL to code first, but I want to do it piece by piece. So I have a Context class like this:</p>
  
  <pre><code>Public Class JournalContext
      Inherits DbContext
  
      Public Sub New()
          MyBase.New("AppDb")
      End Sub
  
      Public Property JournalEntries As IDbSet(Of JournalEntry)
  
      Protected Overrides Sub OnModelCreating(ByVal modelBuilder As System.Data.Entity.ModelConfiguration.ModelBuilder)
  
          modelBuilder.Entity(Of JournalEntry).Property(Function(e) e.Id).HasColumnName("JournalEntryId")
      End Sub
  
  End Class
  </code></pre>
  
  <p>EF is complaining when I use this class about other Entity types that has no key defined. But I don't want them to be in my model for EF.</p>