为什么变量不用指定类型？(50)

ALTER PROCEDURE [dbo].[p_sysnewdoccode] @formid formid,@opid orgcode,@doccodedo
ccode output ASdeclare @curcode integerdeclare @codeflag varchar(10)declare @codelength int select @codeflag = codeflag,@codelength = isnull(codelength,0),@curcode = curcode from gdoctype where formid = @formidif @@rowcount = 0 begin
raiserror ('未发现规定的功能号',16,1) returnend.
......代码末完--------------------------------------------------------------------------------@formid formid,@opid orgcode,@doccodedo
ccode output这里为什么不用指定变量类型？@formid formid------formid有什么作用？谢谢~~~~

formid,orgcode,doccode 这些是自定义类型吧

接受答案了.