Question

如果我没有在模型（帐户）中设置default_scope，只需调用Account.first，将返回哪个项目？

这是一个例子：帐户表有5条记录，Account.all返回：

  Account.all.map{ |x| {id: x.id, name: x.name, created_at: x.created_at, updated_at:x.updated_at}}
  Account Load (0.5ms)  SELECT "accounts".* FROM "accounts"
=> [{:id=>2,
  :name=>"Hessel, Kirlin and Gulgowski",
  :created_at=>Wed, 04 Sep 2013 00:44:33 EDT -04:00,
  :updated_at=>Wed, 04 Sep 2013 00:44:33 EDT -04:00},
 {:id=>3,
  :name=>"Hessel, Kirlin and Gulgowski",
  :created_at=>Wed, 04 Sep 2013 00:44:34 EDT -04:00,
  :updated_at=>Wed, 04 Sep 2013 00:44:34 EDT -04:00},
 {:id=>4,
  :name=>"Hessel, Kirlin and Gulgowski",
  :created_at=>Wed, 04 Sep 2013 00:44:34 EDT -04:00,
  :updated_at=>Wed, 04 Sep 2013 00:44:34 EDT -04:00},
 {:id=>5,
  :name=>"Hessel, Kirlin and Gulgowski",
  :created_at=>Wed, 04 Sep 2013 00:44:35 EDT -04:00,
  :updated_at=>Wed, 04 Sep 2013 00:44:35 EDT -04:00},
 {:id=>1,
  :name=>"EIS",
  :created_at=>Wed, 04 Sep 2013 00:44:31 EDT -04:00,
  :updated_at=>Wed, 04 Sep 2013 00:44:32 EDT -04:00}]

Account.first返回id为2的记录，我没有在模型中设置default_scope，为什么id为2而不是id为1？

谢谢！

更新：我喜欢这个答案（https://stackoverflow.com/a/4986620/655621）

Answer 1

我的理解是，在没有订单的情况下，将使用id的默认订单，但至少在3.2.13中似乎不是这种情况

2.0.0p247 :001 > Book.first
  Book Load (60.0ms)  SELECT "books".* FROM "books" LIMIT 1

所以最近的版本可能会有代码更改。你用的是哪个版本？

activerecord模型的默认排序顺序？

1 个答案: