Ruby/Rails - 检查子 ID 是否存在于 HABTM 关系记录中

发布于 2024-12-10 04:45:24 字数 823 浏览 0 评论 0原文

我有一组名为“任务”和“帖子”的资源，并且彼此之间存在 has_and_belongs_to_many (HABTM) 关系。

还有一个连接它们的值的连接表。

create_table 'posts_tasks', :id => false do |t|
   t.column :post_id, :integer
   t.column :task_id, :integer
end

所以我的问题是如何检查从 @post.tasks 创建的数组中是否存在特定任务的 id？

irb(main):011:0> @post = Post.find(1)
=> #<Post id: 2, comment: "blah blah", created_at: "2011-10-18 03:40:30", updated_at:
irb(main):012:0> @post.tasks
=> [#<Task id: 1, description: "Test 1", created_at: "2011-10-18 03:
   22:05", updated_at: "2011-10-18 03:22:05">, #<Task id: 3, description: "Test 3",
   created_at: "2011-10-18 03:22:21", updated_at: "2011-10-18 03:22:21
    ">]

所以我的问题是 ruby 的编写方式是什么“@task = Task.find(2)”是否存在于 @post.tasks 中，如果存在则返回 true 或 false？

原文

I have a set of resources called Tasks and Posts and there are in a has_and_belongs_to_many (HABTM) relationship with each other.

There is also a join table connecting their values.

create_table 'posts_tasks', :id => false do |t|
   t.column :post_id, :integer
   t.column :task_id, :integer
end

So my question is how do I check to see if the id of a specific task exists within the array created from @post.tasks?

irb(main):011:0> @post = Post.find(1)
=> #<Post id: 2, comment: "blah blah", created_at: "2011-10-18 03:40:30", updated_at:
irb(main):012:0> @post.tasks
=> [#<Task id: 1, description: "Test 1", created_at: "2011-10-18 03:
   22:05", updated_at: "2011-10-18 03:22:05">, #<Task id: 3, description: "Test 3",
   created_at: "2011-10-18 03:22:21", updated_at: "2011-10-18 03:22:21
    ">]

So my question is whats the ruby way for writing does "@task = Task.find(2)" exist within @post.tasks and if so return true or false?

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

离笑几人歌 2024-12-17 04:45:24

@post.tasks.where(:id => task_id).present?

与 Gabelsman 的建议相比要轻得多。

@post.tasks.where(:id => task_id).present?

Is much lighter compared to what Gabelsman has suggested.

回复收藏 0 原文

っ左 2024-12-17 04:45:24

@post.tasks.map(&:id).include?(task_id)

其中 task_id 是您要检查的任务的 ID。为了稍微解释一下这一点，您将获取任务列表，将它们映射到其 id 数组，然后检查有问题的 id 是否在该数组中。如果您不熟悉map，您应该查看一下，它非常棒。

ruby-docs

@post.tasks.map(&:id).include?(task_id)

Where task_id is the id of the task you want to check. To explain this a little bit, you're taking the list of tasks, mapping them to an array of their ids, and then checking to see if the id in question is in that array. If you're not familiar with map you should check it out, it's awesome.

ruby-docs

回复收藏 0 原文