has_many：通过不加载记录
我有一个Rails 5.2.1应用程序，其中关系的每个步骤都有效，但has_many :through版本没有。 设置有点奇怪，但我觉得我已经正确设置了一切，所以我有点难过。
鉴于此代码：
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的每一步：通过工作：
# 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]] => # # 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]] => # # 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
尽管如此，在Postgres中运行生成的查询仍然有效：
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)
运行Contact.first.concepts.to_sql会产生：
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'
通过psql运行该查询工作正常，从inventory__c表返回正确的记录。
反过来也有同样的问题：
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]] => # 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]] => # 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：一切似乎都正确连接，为什么通过版本不工作呢？ 任何帮助，将不胜感激。
谢谢！ ❤️
感谢@ Zabba关于SalesforceModel的评论，我能够找到问题所在。 从根本上说，就是这样：
class ContentAccess < ApplicationRecord
应该是：
class ContentAccess < SalesforceModel # <-- it was using the wrong table, effectively.
这是令人痛苦的一周，但现在好多了。 😀