rails3activerecord-for:生成了错误的sql

我有以下两门课。

class Customer < ActiveRecord::Base
 set_table_name "customer"
 set_primary_key "customerId"
 has_many :new_orders, :foreign_key => "customerid", :primary_key => "customerId", :class_name => "NewOrder"
end

class NewOrder < ActiveRecord::Base
 set_table_name "viewNewOrders"
 set_primary_key "orderid"
 belongs_to :customer, :foreign_key => "customerid", :primary_key => "customerId"
end

我不能触摸数据库来更改任何表、视图或列名。

这非常有效:

new_orders_last_2_weeks = 
 NewOrder.where("orderdate >= :start and orderdate < :end", 
 {:start => period_start, :end => period_end})

new_orders_last_2_weeks = 
 NewOrder.joins(:customer).where("orderdate >= :start and orderdate < :end", 
 {:start => period_start, :end => period_end})

生成错误的sql:

SELECT     `viewNewOrders`.* FROM       `viewNewOrders`  INNER JOIN `customer` ON `customer`.`customerId` IS NULL WHERE     (orderdate >= '2010-09-02' and orderdate < '2010-09-16')

谢谢。