Entity Type 'AstNode' has no key defined

Question

I'm porting a data model from EF4 to EF6 Code First. I'm getting the following message when the database creation is attempted. I'm at a loss to understand what is causing this. I don't have any Context, AstNode or JSParser entities. It is also not looking in the Models namespace:

var context = QPDataContext.Create();
var session = context.DataSessions.FirstOrDefault(ds => ds.DataSessionId = sessionId); 

Throws this exception:

{"One or more validation errors were detected during model generation:

   QPWebRater.DAL.Context: : EntityType 'Context' has no key defined. Define the key for this EntityType. 
   QPWebRater.DAL.AstNode: : EntityType 'AstNode' has no key defined. Define the key for this EntityType.
   QPWebRater.DAL.JSParser: : EntityType 'JSParser' has no key defined. Define the key for this EntityType.
   (many more similar errors snipped). 
"}

Here is my database context (I've simplified it a bit):

QPWebRater.DAL.QPDataContext.cs:

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Data.Entity.Core;
using System.Data.Entity.Validation;
using System.Diagnostics;
using System.Linq;
using System.Text.RegularExpressions;
using System.Web;
using Microsoft.Ajax.Utilities;
using QPWebRater.Models;
using QPWebRater.Utilities;

namespace QPWebRater.DAL
{
    public class QPDataContext : DbContext
    {
        public QPDataContext()
            : base("DefaultConnection")
        {
            Database.SetInitializer<QPDataContext>(new CreateDatabaseIfNotExists<QPDataContext>());
        }

        public static QPDataContext Create()
        {
            return new QPDataContext();
        }

        public DbSet<DataSession> DataSession { get; set; }
        public DbSet<Document> Documents { get; set; }
        public DbSet<Driver> Drivers { get; set; }
        public DbSet<Location> Locations { get; set; }
        public DbSet<Lookup> Lookups { get; set; }
        public DbSet<Quote> Quotes { get; set; }
        public DbSet<Vehicle> Vehicles { get; set; }
        public DbSet<Violation> Violations { get; set; }
     }
}

QPWebRater.Models.DatabaseModels.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace QPWebRater.Models
{

    public partial class DataSession
    {
        public DataSession()
        {
            this.Vehicles = new HashSet<Vehicle>();
            this.Drivers = new HashSet<Driver>();
            ...
        }

        public string DataSessionId { get; set; }
        public System.DateTime Timestamp { get; set; }

        ...
    }

    public partial class Document
    {
        public int DocumentId { get; set; }
        public int QuoteId { get; set; }
        public string DocumentType { get; set; }
        public string Url { get; set; }
        public string Description { get; set; }

        public virtual Quote Quote { get; set; }
    }

    public partial class Driver
    {
        public Driver()
        {
            this.Violations = new HashSet<Violation>();
        }

        public int DriverId { get; set; }
        public string DataSessionId { get; set; }
        ...
    }
}

Answer 1

I solved this by examining all of the DbSet definitions. I had pared down the data model while also upgrading it. I had removed the Lookup model class but neglected to also remove the DbSet<Lookup> Lookups { get; set; } property.

This resulted in the class being resolved as Microsoft.Ajax.Utilities.Lookup. At runtime, EntityFramework tried to add a corresponding database table which failed miserably. If you are running into a similar problem then double check the generic types in your DbSet properties.