殘廢 named_scope

in ActiveRecord, 問題良多的版本（隨時爛掉都不奇怪？）：

named_scope :for_visitor, lambda{ |visitor, user|
  {:conditions =>
     "permissions.#{user.relationship(visitor)} != #{Permission.enum[:none]} AND
#{table_name}.status = 1", # 1 is :common, see app/datamapper/abstract/photo_album.rb
   :include    => :permission}
}

看看人家 DataMapper 多漂亮...

def self.for_visitor visitor, user
  all(permission.send(user.relationship(visitor)).not => :none,
      :status => :common)
end

另一件事，DateTime.new(0) 在 AR 的 DateTime 好像讀不出來...

photo.created_at # => nil in AR, DateTime(0) in DM.

只好改成 1970 試試看吧...