Question

"unless articles.count == 0"过滤器中的条件before_destroy不起作用。

有没有人有类似的问题？

class Category

has_many :articles
before_destroy :ensure_has_no_articles

private

def ensure_has_no_articles
  unless articles.count == 0
    errors[:base] << "cannot delete category that has articles"
    return false
  end
end

Answer 1

尝试：

class Category

has_many :articles
before_destroy :ensure_has_no_articles

private

def ensure_has_no_articles
    return true if articles.count == 0
    errors[:base] << "cannot delete category that has articles"
    return false
end

<强>更新

class Category < ActiveRecord::Base
  has_many :articles, :dependent => :restrict_with_error

Answer 2

正如对类似问题的回答所述：https://stackoverflow.com/a/5520381/580346如果你想要调用destroy，你需要返回true。您的ensure_has_no_articles始终返回false。 @ sunil-b-n提供的答案可以帮到你。

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Answer 3

此方法已根据this rails issue弃用

解决此问题的最佳方法

class Category

has_many :articles
before_destroy :ensure_has_no_articles

private

def ensure_has_no_articles
  unless articles.count == 0
    errors[:base] << "cannot delete category that has articles"
    throw(:abort)
  end
end

before_destroy回调（Rails）中的条件不起作用

3 个答案: