Because the database table use has the limitation,the PDF document format is the international general electronic documents exchange fact standard,the PDF documents may read,the edition,the issue under each kind of platform.

• 由于数据库表的应用具有局限性,PDF文件格式是国际通用的电子文档交换事实标准,PDF文档可以在各种平台下阅读、编辑、发布。