WebActiveRecord::Base.connected_to(role: :reading, shard: :shard_one) do Person.first # Lookup record from read replica of shard one end 7 Activating Automatic Shard Switching Applications are able to automatically switch shards … Webone includes a tested solution, plus a discussion of how and why it works, so that you can adapt the techniques to similar situations. Topics include: Modeling data with the ActiveRecord library Setting up views with ActionView and RHTML templates Building your application's logic into ActionController

似ているようで全然違う!?Activerecordにおけるincludesとjoinsの …

WebConnection to multiple databases in different models. Connections are usually created through ActiveRecord::Base.establish_connection and retrieved by ActiveRecord::Base.connection. All classes inheriting from ActiveRecord::Base will use this connection. But you can also set a class-specific connection. WebActiverecord brainspec/enumerize为默认值抛出mysql错误 activerecord ruby-on-rails-4; Activerecord Rails 4语法，用于将参数或lambda添加到includes条件或将参数传递到关系范围 activerecord ruby-on-rails-4; Activerecord Yii：通过一个表到另一个表的关系 … greensleeves song clarinet

All About ActiveRecord Scopes - DEV Community

Webdistinct (value = true) Link. Specifies whether the records should be unique or not. For example: User.select(:name) # Might return two records with the same name User.select(:name).distinct # Returns 1 record per distinct name User.select(:name).distinct.distinct(false) # You can also remove the uniqueness. WebActive Record queries return relations to be lazy. There’s basically no reason to actually tell the database to execute a query until the very last possible minute. ... #includes basically takes the name of one or more associations that you’d like to load at the same time as your original object and brings them into memory. You can chain it ... Web問題是每個查詢花費100毫秒，並且由於ActiveRecord正在生成的單個查詢的數量，一些控制器操作需要很長時間才能完成。 另一個問題是我不能使用AR includes（）（它只生成一個查詢），因為我遇到了AR-sqlserver-adapter和unicode字符串忽略索引的問題，我正在從sql查 … greensleeves talbot avenue sutton coldfield