mysql - Rails 在连接后从所有表中获取列名

Question

我正在尝试从多个表中获取列名，这些表已执行联接以将它们组合起来。

我尝试执行以下操作:

User.joins(:user_account, :user_file, :user_education).column_names 

但这只是从用户返回列名称，就好像我刚刚完成了以下操作:

User.column_names 

有谁知道如何从联接中获取所有列名称？似乎并不经常需要这样做，因为网上似乎没有太多关于它的信息。我需要它来验证用户参数。

谢谢!

编辑:

用户表中的列名称:

["id", "status", "accepted_terms", "created_at", "updated_at", "email", "encrypted_password", "reset_password_token", "reset_password_sent_at", "remember_created_at", "sign_in_count", "current_sign_in_at", "last_sign_in_at", "current_sign_in_ip", "last_sign_in_ip", "confirmation_token", "confirmed_at", "confirmation_sent_at", "unconfirmed_email", "provider", "uid"]

User_account 表中的列名称:

 ["first_name", "last_name", "phone_number", "address"]

我希望能够获取列名称的完整列表，即

["id", "status", "accepted_terms", "created_at", "updated_at", "email", "encrypted_password", "reset_password_token", "reset_password_sent_at", "remember_created_at", "sign_in_count", "current_sign_in_at", "last_sign_in_at", "current_sign_in_ip", "last_sign_in_ip", "confirmation_token", "confirmed_at", "confirmation_sent_at", "unconfirmed_email", "provider", "uid", "first_name", "last_name", "phone_number", "address"]

我需要什么方法才能准确获取该列表？我已经尝试过

User.joins(:user_account).column_names

但这只是给了我第一组列名，即用户表中的列名(而不是用户帐户表中的列名)。

Answer 1

您可以简单地执行以下操作:

User.column_names + UserAccount.column_names

等等。 Rails 从 ActiveRecord 类而不是 SQL 关系中检索列名。

UPD。或者更惯用的

[User, UserAccount, UserFile, UserEducation].flat_map(&:column_names).uniq