Ruby on rails 模型没有像我认为的那样连接

为什么我会在投标中收到此错误

=>  undefined method `request_for_proposal' for  
# <ActionView::Helpers::FormBuilder:0x002aaad671c9c8>  

=>未定义的方法“请求建议书”
#   

投标申请书有很多投标
投标属于征求建议书

====================================================
Inside views/bids/_form.html.erb

  <div class="field">  
    <%= bid.label :vendor_name %>  
    <%= bid.select :vendor_id, bid.request_for_proposal.vendors.collect { |rfpvi|  
        [rfpvi.friendly_name + "  :  " + rfpvi.rfp_number, rfpvi.id] } %>  
  </div>  

====================================================
内部视图/bids/_form.html.erb

在投标中，我需要通过RFP获得“受邀的供应商”，以便我以后可以限制或限制实际提交投标的供应商

class Bid < ActiveRecord::Base

  attr_accessible :cost, :request_for_proposal_id, :vendor_id

  belongs_to :request_for_proposal
  belongs_to :vendor
------------------------------------------------

mysql> desc bids;
+-------------------------+---------------+------+-----+---------+----------------+
| Field                   | Type          | Null | Key | Default | Extra          |
+-------------------------+---------------+------+-----+---------+----------------+
| id                      | int(11)       | NO   | PRI | NULL    | auto_increment |
| cost                    | decimal(10,0) | YES  |     | NULL    |                |
| request_for_proposal_id | int(11)       | YES  | MUL | NULL    |                |
| vendor_id               | int(11)       | YES  | MUL | NULL    |                |
| contact_id              | int(11)       | YES  | MUL | NULL    |                |
| created_at              | datetime      | NO   |     | NULL    |                |
| updated_at              | datetime      | NO   |     | NULL    |                |
+-------------------------+---------------+------+-----+---------+----------------+  

================================================
class RequestForProposal < ActiveRecord::Base

  attr_accessible   :rfp_number, :name, :description, :title,
                    :contact_id, :business_owner_id

  has_many   :bids
  has_many   :rfp_vendors
  has_many   :vendors, :through => :rfp_vendors

  has_and_belongs_to_many   :business_owners, :class_name => :Contact,
                            :foreign_key => :business_owner_id
  has_and_belongs_to_many   :evaluators,      :class_name => :Contact,
                            :foreign_key => :evaluator_id
 ----------------------------------------------- 

mysql> desc request_for_proposals;
+----------------------------+--------------+------+-----+---------+----------------+
| Field                      | Type         | Null | Key | Default | Extra          |
+----------------------------+--------------+------+-----+---------+----------------+
| id                         | int(11)      | NO   | PRI | NULL    | auto_increment |
| rfp_number                 | varchar(255) | NO   |     | NULL    |                |
| contact_id                 | int(11)      | YES  |     | NULL    |                |
| vendor_id                  | int(11)      | YES  |     | NULL    |                |
| name                       | varchar(255) | NO   |     | NULL    |                |
| description                | varchar(255) | YES  |     | NULL    |                |
| title                      | varchar(255) | NO   |     | NULL    |                |
| bid_id                     | int(11)      | YES  |     | NULL    |                |
| business_owner_id          | int(11)      | YES  |     | NULL    |                |
| evaluator_id               | int(11)      | YES  |     | NULL    |                |
| created_at                 | datetime     | NO   |     | NULL    |                |
| updated_at                 | datetime     | NO   |     | NULL    |                |
+----------------------------+--------------+------+-----+---------+----------------+

================================================
class Vendor < ActiveRecord::Base

    attr_accessible :friendly_name

    has_many :rfp_vendors
    has_many :request_for_proposals, :through => :rfp_vendors
    has_many :bids
------------------------------------------------

mysql> desc vendors;
+-------------------------+--------------+------+-----+---------+----------------+
| Field                   | Type         | Null | Key | Default | Extra          |
+-------------------------+--------------+------+-----+---------+----------------+
| id                      | int(11)      | NO   | PRI | NULL    | auto_increment |
| friendly_name           | varchar(255) | YES  |     | NULL    |                |
| created_at              | datetime     | NO   |     | NULL    |                |
| updated_at              | datetime     | NO   |     | NULL    |                |
+-------------------------+--------------+------+-----+---------+----------------+

================================================
================================================

mysql> desc bids_contacts;
+------------+---------+------+-----+---------+-------+
| Field      | Type    | Null | Key | Default | Extra |
+------------+---------+------+-----+---------+-------+
| bid_id     | int(11) | NO   |     | NULL    |       |
| contact_id | int(11) | NO   |     | NULL    |       |
+------------+---------+------+-----+---------+-------+

mysql> desc bids_vendors;
+-----------+---------+------+-----+---------+-------+
| Field     | Type    | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+-------+
| bid_id    | int(11) | NO   |     | NULL    |       |
| vendor_id | int(11) | NO   |     | NULL    |       |
+-----------+---------+------+-----+---------+-------+

mysql> desc rfp_vendors;
+-------------------------+----------+------+-----+---------+----------------+
| Field                   | Type     | Null | Key | Default | Extra          |
+-------------------------+----------+------+-----+---------+----------------+
| id                      | int(11)  | NO   | PRI | NULL    | auto_increment |
| vendor_id               | int(11)  | YES  |     | NULL    |                |
| request_for_proposal_id | int(11)  | YES  |     | NULL    |                |
| created_at              | datetime | NO   |     | NULL    |                |
| updated_at              | datetime | NO   |     | NULL    |                |
+-------------------------+----------+------+-----+---------+----------------+

class-Biddesc；
+-------------------------+---------------+------+-----+---------+----------------+
|字段|类型|空|键|默认|额外|
+-------------------------+---------------+------+-----+---------+----------------+
|id | int（11）| NO | PRI | NULL |自动增量|
|成本|十进制（10,0）|是| |空||
|申请建议书id（11）|是| MUL |空||
|供应商id | int（11）|是| MUL | NULL ||
|联系方式| id | int（11）|是| MUL | NULL ||
|创建于|日期时间|否|空||
|更新时间为|日期时间|否|空||
+-------------------------+---------------+------+-----+---------+----------------+  
================================================
类RequestForProposal:rfp\u供应商
拥有并且属于许多：企业主，：class\u name=>：联系人，
：foreign\u key=>：企业\u所有者\u id
拥有且属于多个：评估者，：class\u name=>：联系人，
：外键=>：计算器\u id
----------------------------------------------- 
mysql>desc request\u for\u建议书；
+----------------------------+--------------+------+-----+---------+----------------+
|字段|类型|空|键|默认|额外|
+----------------------------+--------------+------+-----+---------+----------------+
|id | int（11）| NO | PRI | NULL |自动增量|
|rfp|U编号| varchar（255）|否|空||
|联系人| id | int（11）|是| |空||
|供应商id | int（11）|是| |空||
|名称| varchar（255）|否| |空||
|description | varchar（255）| YES | | NULL ||
|标题| varchar（255）|否| |空||
|投标书| id | int（11）|是| |空||
|企业|所有者| id | int（11）|是| |空||
|求值器| id | int（11）| YES | | NULL ||
|创建于|日期时间|否|空||
|更新时间为|日期时间|否|空||
+----------------------------+--------------+------+-----+---------+----------------+
================================================
类供应商:rfp\u供应商
有很多：出价
------------------------------------------------
mysql>desc供应商；
+-------------------------+--------------+------+-----+---------+----------------+
|字段|类型|空|键|默认|额外|
+-------------------------+--------------+------+-----+---------+----------------+
|id | int（11）| NO | PRI | NULL |自动增量|
|友好的名称| varchar（255）|是| |空||
|创建于|日期时间|否|空||
|更新时间为|日期时间|否|空||
+-------------------------+--------------+------+-----+---------+----------------+
================================================
================================================
mysql>desc bids\u联系人；
+------------+---------+------+-----+---------+-------+
|字段|类型|空|键|默认|额外|
+------------+---------+------+-----+---------+-------+
|投标书| id | int（11）| NO | | NULL ||
|联系方式| id | int（11）| NO | | NULL ||
+------------+---------+------+-----+---------+-------+
mysql>desc出价与供应商；
+-----------+---------+------+-----+---------+-------+
|字段|类型|空|键|默认|额外|
+-----------+---------+------+-----+---------+-------+
|投标书| id | int（11）| NO | | NULL ||
|供应商id | int（11）| NO | | NULL ||
+-----------+---------+------+-----+---------+-------+
mysql>desc rfp\u供应商；
+-------------------------+----------+------+-----+---------+----------------+
|字段|类型|空|键|默认|额外|
+-------------------------+----------+------+-----+---------+----------------+
|id | int（11）| NO | PRI | NULL |自动增量|
|供应商id | int（11）|是| |空||
|申请建议书id（11）|是| | N