Rails Code Review 2: 不要循环ActiveRecord

hideto

THE WRONG WAY:
@a = A.find_by_name("hideto")@list = []@a.bs.each do |b|  b.cs.each do |c|    @list << c if c.ccc?  endend
这样将产生许多条SQL语句

THE RIGHT WAY:
@a = A.find_by_name("hideto", {:include => {:bs => :cs}})@list = []@a.bs.each do |b|  b.cs.each do |c|    @list << c if c.ccc?  endend
这样只产生一条SQL语句就完成了所有的查询