05_传智播客hibernate教程_实体对象的三种状态与saveOrUpdate方法 2 关于delete后的状态

在 05_传智播客hibernate教程_实体对象的三种状态与saveOrUpdate方法 1 中 我提出了一个疑问：

持久对象在session被删除后，那么这个对象是什么状态？

 

1 关于 delete Session.delete() will remove an object's state from the database. Your application, however, 

 

 

can still hold a reference to a deleted object. It is best to think of delete() as making a persistent

instance, transient.

sess.delete(cat);

You can delete objects in any order, without risk of foreign key constraint violations. It is still

possible to violate a NOT NULL constraint on a foreign key column by deleting objects in the wrong

order, e.g. if you delete the parent, but forget to delete the children.

（删除一个瞬时对象是不会报错的）

 

 

比较特殊的是 删除后对象是有identifier值,但数据库没有这条记录

 

对这个对象进行save没有问题

                       update铁定报错

                       saveOrUpdate 铁定报错

原因见04_传智播客hibernate教程_Session接口及getloadpersist方法 2

所以在session删除后，还可能用这个对象进行数据库交互的 推荐将 identifier  设定成 unsaved-value值