ruby-on-rails - Rails 3 find_or_create 由多个属性 mongoid

Question

在这个链接Rails find_or_create by more than one attribute？可以将多个属性与活动记录一起使用。

如何在 mongoid 中使用多个属性？

谢谢

Answer 1

If you look at the source in lib/mongoid/finders.rb:

# Find the first +Document+ given the conditions, or creates a
# with the conditions that were supplied.
    ...
# @param [ Hash ] attrs The attributes to check.
#
# @return [ Document ] A matching or newly created document.
def find_or_create_by(attrs = {}, &block)
    find_or(:create, attrs, &block)
end

you can see that find_or_create_by accepts a {} as the first argument. You can just pass in several conditions at once

something.find_or_create_by(name: 'john', age: 20)

and it should work.

Answer 2

从查询的 mongoid 文档中：

Model.find_or_create_by

通过提供的属性查找文档，如果没有找到，则创建并返回一个新持久的文档。

Answer 3

克里斯托弗，

我最近遇到了一个类似的问题，并在阅读了 mongoid git 存储库中的源代码后最终解决了这个问题：

在 mongoid 3.1.0 稳定分支中，这有效

    @new_object = NewObject.find_or_create_by(indexed_attribute: my_unique_value,
                                                        :attributeA => value,
                                                        :attributeB => value)