Question

我有一个模特：

def get_all_word_combinations(str, min_length)
    chars = str.split('')
    all_results = []

    (min_length..str.size).each do |x|
      chars.each_cons(x) do |r|
        all_results << r.join
      end
    end
    return all_results
  end

和

class Entry < ActiveRecord::Base
  belongs_to :organization
  belongs_to :detail_organization, class_name: "Organization"
end

我能成功：

class Organization < ActiveRecord::Base
  has_many :entries
end

但我一直在研究一个返回一个相当大的数据集的查询，该数据集被导出到需要拔除的xls。我试过了：

> entry = Entry.last.detail_organization
  Entry Load (0.5ms)  SELECT  "entries".* FROM "entries" ORDER BY "entries"."id" DESC LIMIT $1  [["LIMIT", 1]]
  Organization Load (0.3ms)  SELECT  "organizations".* FROM "organizations" WHERE "organizations"."id" = $1 LIMIT $2  [["id", 69], ["LIMIT", 1]]
=> #<Organization:0x007fcabcabc
 id: 69,
 name: "Detail Office",
 code: "DFO",
 classification_id: 4,
 active: true,
 created_at: Thu, 05 Jan 2017 21:49:48 UTC +00:00,
 updated_at: Thu, 05 Jan 2017 21:49:48 UTC +00:00>

有和没有包括相关组织表，但似乎无法与pluck建立联系。

有趣的是：

[111] pry(main)> @entries = Entry.scheduled_between(start_date, end_date).pluck('detail_organization.name')
   (0.6ms)  SELECT detail_organization.name FROM "entries" INNER JOIN "daily_logs" ON "daily_logs"."id" = "entries"."daily_log_id" WHERE ("daily_logs"."calendar_date" BETWEEN $1 AND $2)  [["calendar_date", "01/06/2017"], ["calendar_date", "01/06/2017"]]
ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR:  missing FROM-clause entry for table "detail_organization"
LINE 1: SELECT detail_organization.name FROM "entries" INNER JOIN "d...
               ^
: SELECT detail_organization.name FROM "entries" INNER JOIN "daily_logs" ON "daily_logs"."id" = "entries"."daily_log_id" WHERE ("daily_logs"."calendar_date" BETWEEN $1 AND $2)
from /Users/atfreeme/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/postgresql_adapter.rb:598:in `async_exec'

至少得到我的ids。

如果我希望对这个问题有足够的描述性，那么任何有任何建议或可能是新方向的人都会这样做？不确定这是PostgreSQL还是ActiveRecord。

Answer 1

问题在于您的查询

ActiveRecord :: StatementInvalid：PG :: UndefinedTable：ERROR：缺少表“detail_organization”的FROM子句条目

ActiveRecord正在尝试搜索表detail_organization，但您的数据库中没有该表

你应该用organizations表查询detail_organization只是一个关联名而不是一个表名

@entries = Entry.scheduled_between(start_date, end_date).joins(:detail_organization).pluck('organizations.name')

使用带有pluck问题的ActiveRecord class_name

1 个答案: