复杂，动态的条款，容易（和安全）

RAILS 2.0 READY! Version 1.2 - released Oct 30, 2007. ChangeLog Overview Do you have a query conditions that look like this? “(name like ‘tim%’) and (age < 10) and (category=’friends’ or category=’family’)” Do you need a way to easily build these queries, with the ability to add more or less conditions based on user input? Enter [RailsWhere] Installation script/plugin install http://railswhere.googlecode.com/svn/tags/railswhere Example Usage Simple User.find(:all, :conditions => Where{|w| w.and "first_name like ?", "#{first_name}%" if params[:first_name] w.and "last_name like ?", "#{last_name}%" if params[:last_name] } Nested conditions ``` w = Where.new for field in [:first_name, :last_name, :phone, :email] w.and("#{field} like ?", params[:s