我在Rawans的桌子上有约30 000份记录,一些原地表有大约30份记录,每个记录都与大约5-8个城市有关。
现在,我想在一些特定城市内 any任何随机交易。
这些城市的名单可以这样作:
@raw_cities = RawCity.where( disabled = ? , 0).map(&:id)
现在需要一笔交易。 我写了一个问题,但时间太长。
@raw_deal = RawDeal.order("RAND()").find(:first,:joins=>[:raw_cities], :conditions=>["raw_cities.id IN (?)",@raw_cities])
The order("RAND()") is probably what s slowing your query down, and since you re only looking for one single deal, you can use a combination of limit and offset to simulate a random order.
类似情况:
@raw_deal = RawDeal.offset(rand(RawDeal.count)).
joins(:raw_cities).
where(raw_cities: @raw_cities).
first
collection_select and select Rails helpers: Which one should I use? I can t see a difference in both ways. Both helpers take a collection and generates options tags inside a select tag. Is there a ...
We ve deployed our rails app to EC2. In our setup, we have two proxies on small instances behind round-robin DNS. These run nginx load balancers for a dynamically growing and shrinking farm of web ...
As part of a web application I need an auth-code to pass as a URL parameter. I am currently using (in Rails) : Digest::SHA1.hexdigest((object_id + rand(255)).to_s) Which provides long strings like : ...
I ve installed RubyCAS-Client version 2.1.0 as a plugin within a rails app. It s working, but I d like to remove the ?ticket= in the url. Is this possible?
I have a these 3 models: class User < ActiveRecord::Base has_many :permissions, :dependent => :destroy has_many :roles, :through => :permissions end class Permission < ActiveRecord::...
I m building an xml document from a hash. The xml attributes need to be in order. How can this be accomplished? hash.to_xml
guys which text editor is good for Rubyonrails? i m using Windows and i was using E-Texteditor but its not free n its expired now can anyone plese tell me any free texteditor? n which one is best an ...
I’m developing an application dedicated to generate statistical reports, I would like that user after saving their stat report they save sql queries too. To do that I wrote the following module: ...