Ruby on rails ActiveRecord:：语句在两个命名空间模型上无效

我必须在同一名称空间中创建两个具有habtm关系的模型

class Resource::Item < ApplicationRecord
    has_and_belongs_to_many :resource_sets, foreign_key: 'resource_item_id', class_name: 'Resource::Set', table_name: 'resource_items_sets'
end

class Resource::Set < ApplicationRecord
    has_and_belongs_to_many :resource_items, foreign_key: 'resource_set_id', class_name: 'Resource::Item', table_name: 'resource_items_sets'
end

到目前为止，一切看起来都很好。正在创建表

resource\u items\u set

，其中包含两列

resource\u item\u id

和

resource\u set\u id

这是模式

create_table "resource_items_sets", id: false, force: :cascade do |t|
    t.bigint "resource_item_id", null: false
    t.bigint "resource_set_id", null: false
end

在创建一个资源项目之后，我得到了如下预期结果

pry(main)> Resource::Item.first.resource_sets
=> #<Resource::Set::ActiveRecord_Associations_CollectionProxy:0x3fdd08748004>

当

resource\u set\u id

到处被声明时，

set\u id

从何而来？如何解决此问题？我想保留这两个名称空间，因为我可能会创建项目并设置更多名称空间

---

非常感谢，伙计们

您需要在联接表的两侧设置外键，因为在您的情况下无法推断它们

在这种情况下，正确的

具有\u且\u属于\u许多

调用应如下所示：

  has_and_belongs_to_many :resource_items,
                          foreign_key: 'resource_set_id',
                          association_foreign_key: 'resource_item_id',
                          class_name: 'Resource::Item',
                          join_table: 'resource_items_sets'
end

及

类资源：：项

---

注意添加的

association\u foreign\u key

选项指定联接表中的其他外键。

尝试在迁移中传递表名，因为表名应该是

resource\u items\u resource\u set

，Rails从表名猜测关联外键。这就成功了！谢谢我不知道我怎么会错过文档中的

关联\u外键

。链接供参考：

pry(main)> Resource::Item.first.resource_sets.count
ActiveRecord::StatementInvalid: PG::UndefinedColumn: ERROR:  column resource_items_sets.set_id does not exist
LINE 1: ...N "resource_items_sets" ON "resource_sets"."id" = "resource_...
                                                         ^
: SELECT "resource_sets"."id" FROM "resource_sets" INNER JOIN "resource_items_sets" ON "resource_sets"."id" = "resource_items_sets"."set_id" WHERE "resource_items_sets"."resource_item_id" = $1 ORDER BY "resource_sets"."name" ASC
from /Users/username/.rvm/gems/ruby-2.6.0/gems/activerecord-5.2.2/lib/active_record/connection_adapters/postgresql_adapter.rb:677:in `async_prepare'
Caused by PG::UndefinedColumn: ERROR:  column resource_items_sets.set_id does not exist
LINE 1: ...N "resource_items_sets" ON "resource_sets"."id" = "resource_...

  has_and_belongs_to_many :resource_items,
                          foreign_key: 'resource_set_id',
                          association_foreign_key: 'resource_item_id',
                          class_name: 'Resource::Item',
                          join_table: 'resource_items_sets'
end

class Resource::Item < ApplicationRecord
  has_and_belongs_to_many :resource_sets,
                          foreign_key: 'resource_item_id',
                          association_foreign_key: 'resource_set_id',
                          class_name: 'Resource::Set',
                          join_table: 'resource_items_sets'
end