object references an unsaved transient instance - save the transient instance before flushing

         

Struts has detected an unhandled exception:

Messages:	object references an unsaved transient instance - save the transient instance before flushing: net.binxia.po.School object references an unsaved transient instance - save the transient instance before flushing: net.binxia.po.School; nested exception is org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: net.binxia.po.School
File:	org/hibernate/engine/internal/ForeignKeys.java
Line number:	249

         小编在使用Hibernate的时候，遇到了这个错误，之前在查询过程中并没有遇到，在update时就出现了这样的错误，问题出在据库表的级联上。

         需要在many-to-one 中加上cascade="save-update,persist"即可