{"url":"https://akinobu.net/entry/2020/08/07/095448","author_name":"kuronekopunk","provider_url":"https://hatena.blog","description":"default: -> { \"now()\" } \u3068\u3044\u3046\u6307\u5b9a\u304c\u3067\u304d\u308b\u3002 create_table \"hoge\" do |t| t.datetime \"hoge_created_at\", default: -> { \"now()\" }, null: false end hoge = Hoge.create hoge.hoge_created_at => nil # DB\u3067\u6642\u9593\u3092\u5165\u308c\u308b\u305f\u3081\u4f5c\u6210\u76f4\u5f8c\u306fnil\u306b\u306a\u3063\u3066\u3057\u307e\u3046 hoge.reload.hoge_created_at => 2020-07-29 10:33:25 +0900 # reload\u3059\u308c\u3070\u3061\u3083\u3093\u3068\u5165\u3063\u3066\u3044\u308b reload\u3057\u306a\u3044\u3068\u3044\u3051\u306a\u2026","blog_url":"https://akinobu.net/","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fakinobu.net%2Fentry%2F2020%2F08%2F07%2F095448\" title=\"Rails migration\u3067default\u306b\u4f5c\u6210\u6642\u306e\u73fe\u5728\u6642\u523b\u3092\u5165\u308c\u308b - \u30ce\u30f3\u30ab\u30d5\u30a7\u30a4\u30f3\u3067\u3042\u306a\u305f\u306b\u3084\u3055\u3057\u3044\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","blog_title":"\u30ce\u30f3\u30ab\u30d5\u30a7\u30a4\u30f3\u3067\u3042\u306a\u305f\u306b\u3084\u3055\u3057\u3044","categories":["Ruby on Rails"],"image_url":null,"author_url":"https://blog.hatena.ne.jp/kuronekopunk/","width":"100%","version":"1.0","height":"190","published":"2020-08-07 09:54:48","provider_name":"Hatena Blog","type":"rich","title":"Rails migration\u3067default\u306b\u4f5c\u6210\u6642\u306e\u73fe\u5728\u6642\u523b\u3092\u5165\u308c\u308b"}