c# - Entity Framework 'column does not allow nulls' -

yet again amazing entity framework has failed make simple, simple... have created basic set of models, company, county, user's have m:1 relationship company. have table created called companyusers believe generate table design like.

however cannot enter basic user database claiming cannot have null userid though setting id.

i understand table design weird, may want switch m:m relationship , having table setup nice that. secondly, having data in 3 tables makes writing sql queries easier because of joins.

exact error:

system.data.sqlclient.sqlexception: cannot insert value null column 'userid', table 'ssi.database.context.software.dbo.users'; column not allow nulls. insert fails.

seed:

var _company = new company()  {     companyid=1,     name="company inc." };  var _counties = new list<county>() {     new county(){ name="place1" },     new county(){ name="place2"} };  context.companies.addorupdate(_company);  var _user = new user() {userid=1, companyid=_company.companyid, company=_company, name = "john smith" };   if (context.counties.count() == 0) {     context.counties.addrange(_counties); }  context.users.addorupdate(_user); 

all models:

company:

public class company {      public company()     {         users = new list<user>();     }      [key]     public int companyid { get; set; }     public string name { get; set; }      public icollection<user> users { get; set; } } 

user:

public class user {     [key]     [databasegenerated(databasegeneratedoption.identity)]     public int userid { get; set; }     public string name { get; set; }       public nullable<int> companyid { get; set; }      [foreignkey("companyid")]     public company company { get; set; } } 

companyuser table:

public class companyusers {     [key]     [column(order = 1)]     public int companyid { get; set; }     [foreignkey("companyid")]     public virtual company company { get; set; }     [key]     [column(order = 2)]     public int userid { get; set; }     [foreignkey("userid")]     public virtual user user{ get; set; } }