如果检查发现的ActiveRecord返回结果 [英] Checking if ActiveRecord find returns a result

问题描述

我想检查是否找到方法返回一个结果。我找到方法如下：

I'm trying to check if a find method returns a result. My find method is the following:

post = Post.find(:all, :conditions => { :url => params['url'] }, :limit => 1)

什么是检查后中包含的结果呢？一个好办法

What would be a good way to check that post contains a result?

推荐答案

查找：所有返回一个空数组（ [] ），如果没有返回行，所以你可以用这种方式：

find :all returns an empty array ([]) if no rows are returned, so you can just use it this way:

post = Post.find(:all, :conditions => { :url => params['url'] }, :limit => 1)

unless post.empty?
  # do something...
end

顺便说一句，如果你这样做查找：所有你会得到一个数组，而不是单行。如果你想得到的只是一个职位，那将是更清洁的使用 find_by 助手或发现：第一个或只是第一来代替：

By the way, if you do find :all you're going to get an array, not a single row. If you're trying to get just one Post, it would be cleaner to use the find_by helper or find :first or just first instead:

post = Post.find_by_url params['url']

# or

post = Post.first :conditions => { :url => params['url'] }

# then...

if post
  # do something...
end

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