尝试干燥,我试图在对象初始化后分配给模型的实例变量。
class WorkNote < ActiveRecord::Base
def after_initialize
self[:clockin]= WorkNote.last_clockout
end
def self.last_clockout
WorkNote.find(:first, :order => "clockout DESC").clockout
end
end
但是,方法调用after_initialize
会导致SystemStackError
:
ActiveRecord::StatementInvalid: SystemStackError: stack level too deep: SELECT * FROM "work_notes" ORDER BY clockout DESC LIMIT 1
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/sqlite_adapter.rb:157:in `execute'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/sqlite_adapter.rb:402:in `catch_schema_changes'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/sqlite_adapter.rb:157:in `execute'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/sqlite_adapter.rb:305:in `select'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:62:in `select_all'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:661:in `find_by_sql'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:1553:in `find_every'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:1510:in `find_initial'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:613:in `find'
from /Users/noob/jobs/app/models/work_note.rb:10:in `last_clockout'
from /Users/noob/jobs/app/models/work_note.rb:6:in `after_initialize'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/callbacks.rb:347:in `send'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/callbacks.rb:347:in `callback'
from /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:1662:in `send'
... 5116 levels...
如果我注释掉after_initialize
,该last_clockout
方法没有问题。当我使用回调before_save
而不是after_initialize
. 为什么会after_initialize
造成这种情况?
谢谢!