Searchlogic gem已安装，但我无法访问方法

Question

我刚刚安装了searchlogic gem，但是当我试图通过控制台访问基本方法时，我得到了以下错误：

>> User.username_not_null
NoMethodError: undefined method `username_not_null' for #<Class:0x1033a1d90>
    from /Library/Ruby/Gems/1.8/gems/searchlogic-2.4.27/lib/searchlogic/named_scopes/conditions.rb:81:in `method_missing'
    from /Library/Ruby/Gems/1.8/gems/searchlogic-2.4.27/lib/searchlogic/named_scopes/association_conditions.rb:19:in `method_missing'
    from /Library/Ruby/Gems/1.8/gems/searchlogic-2.4.27/lib/searchlogic/named_scopes/association_ordering.rb:27:in `method_missing'
    from /Library/Ruby/Gems/1.8/gems/searchlogic-2.4.27/lib/searchlogic/named_scopes/ordering.rb:30:in `method_missing'
    from /Library/Ruby/Gems/1.8/gems/searchlogic-2.4.27/lib/searchlogic/named_scopes/or_conditions.rb:28:in `method_missing'
    from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:1959:in `method_missing'
    from (irb):1

我仍然在掌握Gems的诀窍，它经常让我上当受骗--有人能给我指出正确的方向来解决这个问题吗？

Answer 1

不要在可以使用Rails的情况下使用Searchlogic：

 User.all(:conditions => ["username IS NOT NULL"])