One to Many association problem in LINQ to SQL

I have the following associated property in my Employee class, where EmployeePhoneNumber is related, as the attributes declare, in the DB.

[TableAttribute(Name = "dbo.EmoployeePhoneNumber")]
public class EmployeePhoneNumber

and

[TableAttribute(Name = "dbo.Employee")]
public class Employee
{
    [ColumnAttribute(IsPrimaryKey = true, IsDbGenerated = true)]
    public int ID { get; set; }

    [Association(Name = "Employee_EmployeePhoneNumbers", ThisKey = "ID", OtherKey = "EmployeeID")]
    public EntitySet<EmployeePhoneNumber> PhoneNumbers { get; set; }
}

When I try and access GetTable<Employee>(), I get the error:

Invalid association mapping for member 'Interview.Web.Models.Employee.PhoneNumbers'. 'Interview.Web.Models.EmployeePhoneNumber' is not an entity.

I am very new to LINQ to SQL, being an EF man u开发者_如何学Csed to the model designer, and I have to code these models by hand.

ColumnAttribute with IsPrimaryKey=true missing in EmployeePhoneNumber