ssh集成关于hibernate问题
Hibernate: update QMAX_GSM_EX_PLAN_GAGES set EXAMINE_PLAN_ID=null where EXAMINE_PLAN_ID=?
[log4j] [ERROR] org.hibernate.util.JDBCExceptionReporter.logExceptions(JDBCExceptionReporter.java:72) - ORA-01407: 无法更新 ("GSM"."QMAX_GSM_EX_PLAN_GAGES"."EXAMINE_PLAN_ID") 为 NULL

[log4j] [ERROR] org.hibernate.util.JDBCExceptionReporter.logExceptions(JDBCExceptionReporter.java:72) - ORA-01407: 无法更新 ("GSM"."QMAX_GSM_EX_PLAN_GAGES"."EXAMINE_PLAN_ID") 为 NULL

[log4j] [ERROR] org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:301) - Could not synchronize database state with session
org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch update
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:249)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:235)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:141)
我在删除时报这种异常，请问怎么解决，急！

------解决方案--------------------
EXAMINE_PLAN_ID
LZ的这个字段，不是主键，要不就是有外键约束，或者有非空设置。
------解决方案--------------------
EXAMINE_PLAN_ID 字段是否有非空的约束
------解决方案--------------------
可能是.hbm.xml的问题，一对多中维护关系交给了哪一方，发.hbm.xml看下