Hibernate的delete笔记 (cascade属性值)

	Session session = HibernateUtil.openSession();

		Transaction tx = null;

		tx = session.beginTransaction();
		
		User user=(User) session.load(User.class, 564);
		
		session.delete(user);
		
		tx.commit();
		
		session.close();

<set name="orders" cascade="save-update" inverse="true" lazy="false"> 


由于一个user对应多个order， 这里user还有外联记录， 所以会报错。

ERROR: ORA-02292: 违反完整约束条件 (ALLENI.FK_QCPYHSS71C9CAMNA3X8K2Q0D9) - 已找到子记录

Exception in thread "main" org.hibernate.exception.ConstraintViolationException: could not execute statement

解决方法是吧User.hbm.xml配置文件的set的cascade属性修改成"delete"。

再次执行程序， hibernate会自动执行两个delete语句：
Hibernate: select user0_.id as id1_2_0_, user0_.test_name as test2_2_0_, user0_.test_age as test3_2_0_ from test_user user0_ where user0_.id=?
Hibernate: select orders0_.customer_id as customer3_2_1_, orders0_.id as id1_0_1_, orders0_.id as id1_0_0_, orders0_.test_name as test2_0_0_, orders0_.customer_id as customer3_0_0_ from test_order orders0_ where orders0_.customer_id=?
Hibernate: delete from test_order where id=?
Hibernate: delete from test_user where id=?


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cascade可以有多种属性值， 如下图所示:



这里我们可以把属性值改成all， 这样一来， 不论是加入数据， 更新，还是删除， hibernate都会帮我们进行自动处理。