如何发出'发现'或'，其中'引发一个RecordNotFound [英] How to issue a 'find' or 'where' that raises a RecordNotFound

问题描述

当我调用找到一个ID，就变成了有针对性的查找，将抛出一个错误RecordNotFound。

When I call a find with an id, it becomes a targeted find, and will throw an error RecordNotFound.

Foo::Bar.find(123) # RecordNotFound if no Bar with id 123 exists.

但是，当我打电话，随着条件的，我得到零，如果未找到：

But when I call that with conditions, I get nil if not found:

Foo::Bar.find(:first, :conditions => [ "lower(name) = ?", name.downcase ])

我想这样的条件搜索引发错误了。我知道我可以做的：

I want such a conditional search to raise an error too. I know I can do:

Foo::Bar.find_by_name!("CocktailBar") #=> raises Recordnotfount if not not found.

但是，只有非常简单的条件。矿井需要更多一点的复杂性;其实是这样的：

But that has only really simple conditions. Mine need a little more complexity; actually something like:

Foo.Bar.select{ |pm| pm.name.downcase =~ /cocktail/}.first

和，如果没有找到，我希望它提高RecordNotFound错误。这是可能的呢？或者我应该简单地增加一些code对证零？如果零？提高自己的错误？如果是这样，我怎么做，在Rails 3的？

And, if nothing is found, I want it to raise the RecordNotFound error. Is that possible at all? Or should I simply add some code to check against nil? and if nil? raise the error myself? And if so, how do I do that in Rails 3?

推荐答案

您最后一款是你需要做的。无论是对证零，或提高自己的异常。为了提高自己的异常，请执行以下操作：

Your final paragraph is what you need to do. Either check against nil, or raise the exceptions yourself. To raise the exception yourself, do the following:

Foo::Bar.find(:first, :conditions => [ "lower(name) = ?", name.downcase ]) || raise(ActiveRecord::RecordNotFound)

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