public class Course : Entity
{
    public string Identification { get; set; }
    public double Price { get; set; }
    public bool Active { get; set; }

    public Guid CourseTypeId { get; set; }
    public virtual CourseType CourseType { get; set; }

    public Guid InstructorId { get; set; }
    public virtual Instructor Instructor { get; set; }

    public ICollection<OrderDetail> OrderDetails { get; set; }

    public ValidationResult ValidationResult { get; set; }

    public bool IsValid()
    {
        ValidationResult = new CourseIsConsistentValidation().Validate(this);

        return ValidationResult.IsValid;
    }
}

public class CourseType : Entity
{
    public string Identification { get; set; }
    public bool Active { get; set; }

    public virtual ICollection<Course> Courses { get; set; }

    public ValidationResult ValidationResult { get; set; }

    public bool IsValid()
    {
        ValidationResult = new CourseTypeIsConsistentValidation().Validate(this);

        return ValidationResult.IsValid;
    }
}

public class Instructor : Entity
{
    public string Identification { get; set; }
    public DateTime BirthDate { get; set; }
    public string Email { get; set; }
    public int LicenseNumber { get; set; }
    public bool Active { get; set; }

    public ICollection<Course> Courses { get; set; }

    public ValidationResult ValidationResult { get; set; }

    public bool IsValid()
    {
        ValidationResult = new InstructorIsConsistentValidation().Validate(this);

        return ValidationResult.IsValid;
    }
}

public IEnumerable<Course> GetActive()
{
    query.AppendLine("SELECT c.Id,");
    query.AppendLine("       c.Identification,");
    query.AppendLine("       c.Price,");
    query.AppendLine("       c.Active,");
    query.AppendLine("       c.CourseTypeId,");
    query.AppendLine("       c.InstructorId,");
    query.AppendLine("       ct.Identification as CourseType,");
    query.AppendLine("       i.Identification as Instructor");
    query.AppendLine("  FROM Courses c");
    query.AppendLine(" INNER JOIN CourseTypes ct");
    query.AppendLine("    ON ct.Id = c.CourseTypeId");
    query.AppendLine(" INNER JOIN Instructors i");
    query.AppendLine("    ON i.Id = c.InstructorId");
    query.AppendLine(" WHERE c.Active = 1");

    return Context.Database.SqlQuery<Course>(query.ToString()).ToList();
}

Context.Database.Connection.Query (Course, CourseType, Instructor)