hibernate 级联删除报更新失败的问题

使用Hibernate框架，做级联删除时，出现一下报错:

org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch update

首先查看级联删除对象的映射配置文件, 是否有配置关联关系；因为级联对应关联太多，这里就不贴了。

再打印sql语句，查询具体是在什么地方出现错误：

Hibernate:     select        purchaseor0_.id as id162_0_,        purchaseor0_.allGoods_id as allGoods2_162_0_,        purchaseor0_.purchaseOrder_id as purchase3_162_0_,        purchaseor0_.planProcure_id as planProc4_162_0_,        purchaseor0_.detectStatus as detectSt5_162_0_,        purchaseor0_.fahuoStatus as fahuoSta6_162_0_,        purchaseor0_.inStoreStatus as inStoreS7_162_0_,        purchaseor0_.isToStock as isToStock162_0_,        purchaseor0_.tuiHuanGoodsId as tuiHuanG9_162_0_,        purchaseor0_.quantity as quantity162_0_,        purchaseor0_.discount as discount162_0_,        purchaseor0_.amount as amount162_0_,        purchaseor0_.taxRate as taxRate162_0_,        purchaseor0_.orderPrice as orderPrice162_0_,        purchaseor0_.withTaxAmount as withTax15_162_0_,        purchaseor0_.orderDate as orderDate162_0_,        purchaseor0_.remark as remark162_0_,        purchaseor0_.packingQuantity as packing18_162_0_,        purchaseor0_.productionLotNumber as product19_162_0_,        purchaseor0_.expirationDate as expirat20_162_0_     from        purchaseOrderItem purchaseor0_     where        purchaseor0_.id=?... ...//查询关联对象的SQLHibernate:     update        detection     set        purchaseOrderItem_id=null     where        purchaseOrderItem_id=?org.hibernate.exception.GenericJDBCException: Could not execute JDBC batch updateat 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:254)at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266)at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:169)at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1001)at com.rhxy.dao_new.BaseSubTableDAO.delete(BaseSubTableDAO.java:299)... ...//exception

注意红色字体部分，问题就出在这里，当前表与detection表存在一对多关系，是双向关联的:

这里是修改前的映射文件描述:

 <set name="detections">            <key>                <column name="purchaseOrderItem_id"/>            </key>            <one-to-many class="com.rhxy.bean_new.procurement.Detection"/>        </set>

添加fetch="join":

 <set name="detections" fetch="join">            <key>                <column name="purchaseOrderItem_id"/>            </key>            <one-to-many class="com.rhxy.bean_new.procurement.Detection"/>        </set>

至此，问题解决；还有需要注意的是detection标准的，关于当前对象是否允许为NULL？ 如果不是，这里也需要调整为允许为NULL

添加fetch="join" 是为了在查询对象的时候，使用外连接来查询关联的detection对象；因为默认是使用延迟加载，所以当你不使用fetch

属性的时候，查询出来的关联对象并不是一个真正的对象，只是一个代理；所以造成更新关联对象失败

关于 fetch属性问题，请查询百度，关于延迟加载的问题；