has_many：通過不加載記錄

Question

我有一個Rails 5.2.1應用程序，關系的每個步驟都可以使用，但是has_many :through版本卻不行。 設置有些奇怪，但是我覺得我已經正確設置了所有內容，所以有點困惑。

給出以下代碼：

class Contact < SalesforceModel
  self.table_name =  'salesforce.contact'
  self.primary_key = 'sfid'

  has_many :content_accesses, foreign_key: 'contact__c', class_name: 'ContentAccess'
  has_many :concepts, through: :content_accesses, source: :inventory
end

class ContentAccess < ApplicationRecord
  self.table_name =  'salesforce.content_access__c'
  self.primary_key = 'sfid'

  belongs_to :inventory, foreign_key: 'inventory__c', inverse_of: :content_accesses, primary_key: 'sfid', class_name: 'Inventory'
  belongs_to :contact, foreign_key: 'contact__c', inverse_of: : content_accesses, primary_key: 'sfid', class_name: 'Contact'
end

class Inventory < SalesforceModel
  self.table_name = 'salesforce.inventory__c'
  self.primary_key = 'sfid'

  has_many :content_accesses, foreign_key: 'inventory__c'
  has_many :contacts, through: :content_accesses
end

has_many的每個步驟：貫穿工作：

# Setup
2.5.1 :001 > contact = Contact.first
  Contact Load (30.6ms)  SELECT  "salesforce"."contact".* FROM "salesforce"."contact" ORDER BY "salesforce"."contact"."sfid" ASC LIMIT $1  [["LIMIT", 1]]
 => #<Contact lastname: "Doe", mailingpostalcode: "90210", name: "John Doe", mobilephone: nil, birthdate: nil, phone: nil, mailingstreet: "123 ABC Street", isdeleted: false, systemmodstamp: "2018-03-16 00:09:01", mailingstatecode: "CA", createddate: "2018-03-15 17:50:44", mailingcity: "LA", mailingcountrycode: "US", firstname: "John", email: "john.doe@realisp.com", sfid: "003m000000txXhwAAE", id: "003m000000txXhwAAE", _hc_lastop: "SYNCED", _hc_err: nil> 

# Accessing related ContentAccess works
2.5.1 :002 > contact.content_accesses.count
   (2.0ms)  SELECT COUNT(*) FROM "salesforce"."content_access__c" WHERE "salesforce"."content_access__c"."contact__c" = $1  [["contact__c", "003m000000txXhwAAE"]]
 => 2 

# Accessing related Inventory, through the related ContentAccess works
2.5.1 :003 > contact.content_accesses.first.inventory  
  ContentAccess Load (0.6ms)  SELECT  "salesforce"."content_access__c".* FROM "salesforce"."content_access__c" WHERE "salesforce"."content_access__c"."contact__c" = $1 ORDER BY "salesforce"."content_access__c"."sfid" ASC LIMIT $2  [["contact__c", "003m000000txXhwAAE"], ["LIMIT", 1]]
  Inventory Load (30.4ms)  SELECT  "salesforce"."inventory__c".* FROM "salesforce"."inventory__c" WHERE "salesforce"."inventory__c"."sfid" = $1 LIMIT $2  [["sfid", "a1mm0000001S9qzAAC"], ["LIMIT", 1]]
 => #<Inventory createddate: "2018-05-23 15:09:41", isdeleted: false, name: "Some Concept Name", systemmodstamp: "2018-05-23 15:09:42", sfid: "a1mm0000001S9qzAAC", id: "a1mm0000001S9qzAAC", _hc_lastop: "SYNCED", _hc_err: nil> 

# Accessing the related inventory through the has_many :through does not work
2.5.1 :004 > contact.concepts.count
   (33.0ms)  SELECT COUNT(*) FROM "salesforce"."inventory__c" INNER JOIN "salesforce"."content_access__c" ON "salesforce"."inventory__c"."sfid" = "salesforce"."content_access__c"."inventory__c" WHERE "salesforce"."content_access__c"."contact__c" = $1  [["contact__c", "003m000000txXhwAAE"]]
 => 0 

不過，在Postgres中運行生成的查詢是可行的：

app_development=# SELECT COUNT(*) FROM "salesforce"."inventory__c" INNER JOIN "salesforce"."content_access__c" ON "salesforce"."inventory__c"."sfid" = "salesforce"."content_access__c"."inventory__c" WHERE "salesforce"."content_access__c"."contact__c" = '003m000000txXhwAAE';
 count 
-------
     2
(1 row)

運行Contact.first.concepts.to_sql會產生：

SELECT "salesforce"."inventory__c".* FROM "salesforce"."inventory__c" INNER JOIN "salesforce"."content_access__c" ON "salesforce"."inventory__c"."sfid" = "salesforce"."content_access__c"."inventory__c" WHERE "salesforce"."content_access__c"."contact__c" = '003m000000txXhwAAE'

通過psql運行該查詢可以正常工作，並從stockstock__c表返回正確的記錄。

反之也有同樣的問題：

2.5.1 :002 > inventory = Inventory.first
  Inventory Load (30.2ms)  SELECT  "salesforce"."inventory__c".* FROM "salesforce"."inventory__c" ORDER BY "salesforce"."inventory__c"."sfid" ASC LIMIT $1  [["LIMIT", 1]]
 => #<Inventory createddate: "2018-05-23 15:09:41", isdeleted: false, name: "Positive Focus", systemmodstamp: "2018-05-23 15:09:42", inventory_unique_name__c: "Inventory 1", sfid: "a1mm0000001S9qzAAC", id: "a1mm0000001S9qzAAC", _hc_lastop: "SYNCED", _hc_err: nil> 
2.5.1 :003 > inventory.content_accesses.first.contact
  ContentAccess Load (0.9ms)  SELECT  "salesforce"."content_access__c".* FROM "salesforce"."content_access__c" WHERE "salesforce"."content_access__c"."inventory__c" = $1 ORDER BY "salesforce"."content_access__c"."sfid" ASC LIMIT $2  [["inventory__c", "a1mm0000001S9qzAAC"], ["LIMIT", 1]]
  Contact Load (30.9ms)  SELECT  "salesforce"."contact".* FROM "salesforce"."contact" WHERE "salesforce"."contact"."sfid" = $1 LIMIT $2  [["sfid", "003m000000txXhwAAE"], ["LIMIT", 1]]
 => #<Contact sfid: "003m000000txXhwAAE", id: "003m000000txXhwAAE", [...etc...] > 
2.5.1 :004 > inventory.contacts.count
   (30.7ms)  SELECT COUNT(*) FROM "salesforce"."contact" INNER JOIN "salesforce"."content_access__c" ON "salesforce"."contact"."sfid" = "salesforce"."content_access__c"."contact__c" WHERE "salesforce"."content_access__c"."inventory__c" = $1  [["inventory__c", "a1mm0000001S9qzAAC"]]
 => 0 

所以：一切似乎都正確連接了，那么貫通版本為什么不起作用？ 任何幫助，將不勝感激。

謝謝！ ❤️

Answer 1

感謝@Zabba提出的有關SalesforceModel的評論，我得以找到問題所在。 從根本上講，是這樣的：

class ContentAccess < ApplicationRecord

應該是：

class ContentAccess < SalesforceModel # <-- it was using the wrong table, effectively.

這是一個令人痛苦的一周，但現在好了。 😀