Bulk Insert and Upsert At some point, we all need to insert multiple records in one go and have found many workarounds when doing so. Well, Rails 6 comes with a new method out of the box—insert_all, similar toupdate_all. It won’t fire any callbacks and will execute a single SQL...
config.consider_all_requests_local是个标记. 如果为 true 则任何携带详细调试信息的错误信息都会被添加到 HTTP 回应(response) 里, 并且Rails::Info控制器会显示应用运行时上下文到/rails/info/properties. 在开发和测试模式默认是 true , 在生产模式是 false. 为了更细致的控制, 将其设置为 false 并在控制器里...
(count=10000)Post.insert_all!((1..count).map{{title:SecureRandom.alphanumeric}})endend Output: Post Exists? (0.1ms) SELECT 1 AS one FROM "posts" LIMIT ? [["LIMIT", 1]] Post Load (8.6ms) SELECT "posts".* FROM "posts" Post Exists? (0.7ms) SELECT 1 AS one FROM "posts" LIMIT...
we will automatically find the nested objects first, then continue down the nest chain to find the target object. This is how Hot Glue assumes all object are 'anchored' to the logged-in user
Rails控制台还显示对应于user.save的SQL命令(即INSERT INTO)“用户”…… 我们在本书中几乎不需要原始SQL 从现在开始我将省略对SQL命令的讨论 但是通过阅读与Active Record命令相对应的SQL可以学到很多东西 您可能已经注意到新用户对象的id和神奇列created_at和updated_at属性的值为nil 让我们看看我们的保存是否改变...
SQL (2.2ms) INSERT INTO "articles" ("body", "created_at", "published_at", "title", "updated_at") VALUES (?,?,?,?,?) [["body", "RailsConf is the official gathering for Rails developers.."], ["created_at", Sat, 13 Apr 2013 15:50:29 UTC ...
在Rails4中的AR Relation 提供了两个更新记录的方法update_all和update其中: update_all 通过一条SQL语句更新多条记录,不能触发callback和validate update 通过N条SQL语句,更新N条记录,其中N取决于其第一个ID参数的个数。 通过上面的方法定义,可以看出,如果你不知道ID的情况下,想更新一组记录并且触发它们各自的cal...
page.insert_html :bottom, 'expenses', :partial => 'expense' page.visual_effect :highlight, "expense-#{@expense.id}" page.replace_html 'total-amount', number_to_currency(@project.total_expenses) page.form.reset 'expense-form' end
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我们在代码中看不到与 INSERT、UPDATE、DELETE 和 SELECT * 查询有关的 SQL 语句,而每个 Model 类都会使用这类查询。这类代码是在后台生成的。但是,旧模式的一个共同特征就是需要复杂的 SQL 语句来检索或汇总数据。另外,Oracle 数据库还提供其他 RDBMS 中没有的强大功能。例如,它可以使用单个层次查询生成数据的...