如何使activerecord-import使用序列

Question

我有以下模型：

                                                  Table "public.models"
        Column        |            Type             | Collation | Nullable |                   Default                   
----------------------+-----------------------------+-----------+----------+---------------------------------------------
 id                   | bigint                      |           | not null | nextval('models_id_seq'::regclass)
 research_provider_id | bigint                      |           | not null | 
 covered_company_id   | bigint                      |           | not null | 
 publication_date     | timestamp without time zone |           | not null | 
 created_at           | timestamp without time zone |           | not null | 
 updated_at           | timestamp without time zone |           | not null | 
 insights_id          | bigint                      |           | not null | nextval('models_insights_id_seq'::regclass)
Indexes:
    "models_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
    "fk_rails_22d32db7ac" FOREIGN KEY (covered_company_id) REFERENCES companies(id)
    "fk_rails_3a764bb9c1" FOREIGN KEY (research_provider_id) REFERENCES companies(id)
Referenced by:
    TABLE "model_product_groups" CONSTRAINT "fk_rails_1866a14ba0" FOREIGN KEY (model_id) REFERENCES models(id)
    TABLE "model_analysts" CONSTRAINT "fk_rails_c7730c705b" FOREIGN KEY (model_id) REFERENCES models(id)

我使用ActiveRecord创建对象，如下所示：

   Model.new(
        # insights_id: 
        research_provider_id: company.id,
        covered_company_id: covered_company_id,
        publication_date:  Time.current - rand(1..20).day,
    ......
   )

要使用models_insights_id_seq序列，我应该向insights_id传递什么值？尝试了DEFAULT，没有传递任何东西，两个都不能使用序列，例如，使用activerecord-import来生成nextval('public.models_insights_id_seq')

注意:这个问题是要指示activerecord-import为insights_id列生成nextval('public.models_insights_id_seq')，而不是关于使用ActiveRecord来获取序列的next值。

Answer 1

今天也面临着同样的问题。只是使用了另一种记录导入方式。不导入AR对象的集合，而是构建一个不带序列参数的属性散列集合，然后通过Model.import导入它们。这种方式对我来说很有效。

举例说明。假设我有一个具有默认序列值的position列：position | integer | not null default nextval('file_exports.task_file_item_position_seq'::regclass)

在此代码中，Postgres将在每个FileExports::TaskFileItem记录中自动设置下一个序列值。

... 
params = file_records.map do |file_record|
  build_file_item_params(file_record) 
end 

def build_file_item_params(file_record) 
  { 
    name: "some_name", 
    link: file_record.file.url 
  } 
end 

FileExports::TaskFileItem.import!(params, validate: true)