Java Hello World通过CheckStyle(Java Hello World to pass CheckStyle)

 出于某种原因，ActiveRecord :: Relation忽略了limit选项。 
 
 在Rails 3中，ActiveRecord实际上不会执行您的查询，直到需要访问结果。 调用last执行此操作（但同样会忽略限制）。 
 
 您可以通过调用查询中的all来告诉ActiveRecord执行查询。 然后，当你last运行时，它会给你你正在寻找的“最后”记录。 
 
@items = Item.where(:user_id => 1).order("updated_at DESC").limit(2)
# @items is an ActiveRecord::Relation here
@oldest_item = @items.last
# Returns "C" instead of "B". This is actually ignoring the `limit` parameter

@items = Item.where(:user_id => 1).order("updated_at DESC").limit(2).all
# @items is an Array of ActiveRecord objects here
@oldest_item = @items.last
# Returns "B"
 
 这对我来说似乎不是预期的行为。 我在rails问题跟踪器中提交了一个错误。 
 
 更新 ：@BaroqueBobcat提交了一个被接受的补丁 ，因此应该在即将发布的Rails 3.1版本中修复。 

For some reason, ActiveRecord::Relation is ignoring the limit option.
 
In Rails 3, ActiveRecord doesn't actually execute your query until need to access the results. Calling last does this (but again, ignores the limit).
 
You can tell ActiveRecord to execute the query by calling all on your query. Then, when you run last on that, it'll give you the "last" record you're looking for.
 
@items = Item.where(:user_id => 1).order("updated_at DESC").limit(2)
# @items is an ActiveRecord::Relation here
@oldest_item = @items.last
# Returns "C" instead of "B". This is actually ignoring the `limit` parameter

@items = Item.where(:user_id => 1).order("updated_at DESC").limit(2).all
# @items is an Array of ActiveRecord objects here
@oldest_item = @items.last
# Returns "B"
 
This doesn't seem like expected behavior to me. I've filed a bug in the rails issues tracker.
 
Update: @BaroqueBobcat submitted a patch which got accepted, so it should be fixed in the upcoming 3.1 release of Rails.