Rails - 最佳实践:如何创建依赖 has_one 关系 [英] Rails - Best-Practice: How to create dependent has_one relations

问题描述

创建 has_one 关系的最佳做法是什么?

What's the best practice to create has_one relations?

例如，如果我有一个用户模型，它必须有一个配置文件...

For example, if I have a user model, and it must have a profile...

我怎么能做到这一点?

一种解决方案是:

# user.rb
class User << ActiveRecord::Base
  after_create :set_default_association

  def set_default_association
    self.create_profile
  end
end

但这似乎不太干净......有什么建议吗?

But that doesn't seem very clean... Any suggestions?

推荐答案

创建 has_one 关系的最佳实践是使用 ActiveRecord 回调 before_create 而不是 after_create.或者使用更早的回调并处理子进程未通过其自己的验证步骤的问题(如果有).

Best practice to create has_one relation is to use the ActiveRecord callback before_create rather than after_create. Or use an even earlier callback and deal with the issues (if any) of the child not passing its own validation step.

因为:

• 通过良好的编码，您有机会在验证失败时向用户显示子记录的验证
• 它更干净并且由 ActiveRecord 明确支持——AR 在保存父记录后(在创建时)会自动填充子记录中的外键.然后 AR 将子记录保存为创建父记录的一部分.

怎么做:

# in your User model...
has_one :profile
before_create :build_default_profile

private
def build_default_profile
  # build default profile instance. Will use default params.
  # The foreign key to the owning User model is set automatically
  build_profile
  true # Always return true in callbacks as the normal 'continue' state
       # Assumes that the default_profile can **always** be created.
       # or
       # Check the validation of the profile. If it is not valid, then
       # return false from the callback. Best to use a before_validation 
       # if doing this. View code should check the errors of the child.
       # Or add the child's errors to the User model's error array of the :base
       # error item
end

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