现在需要将一个多对多的关系拆分,比如学生和老师之间的关系,拆成两个多对一,并且中间表也需要实体类、配置文件。我大概是这样做的:
学生表:
<hibernate-mapping default-lazy="false">
<class name="Student" table="t_stutent">
<id name="id" type="long">
<column name="ID" precision="20" scale="0"/>
<generator class="sequence">
<param name="sequence">SEQ_STUTENT</param>
</generator>
</id>
<set name="Teacher" inverse="true" lazy="false" cascade="all-delete-orphan">
<key column="STUTENT_ID"/>
<one-to-many class="StudentTeacher"/>
</set>
</class>
</hibernate-mapping>教师表:
<hibernate-mapping default-lazy="false">
<class name="Teacher" table="t_teacher">
<id name="id" type="long">
<column name="ID" precision="20" scale="0"/>
<generator class="sequence">
<param name="sequence">SEQ_TEACHER</param>
</generator>
</id>
<set name="stutent" inverse="true" lazy="false" cascade="all-delete-orphan">
<key column="TEACHER_ID"/>
<one-to-many class="StutentTeacher"/>
</set>
</class>
</hibernate-mapping>中间表(即StutentTeacher类对应的表):
<hibernate-mapping default-lazy="false">
<class name="StutentTeacher" table="t_stu_tea">
<id name="id" type="long">
<column name="ID" precision="20" scale="0"/>
<generator class="sequence">
<param name="sequence">SEQ_STU_TEA</param>
</generator>
</id>
<property name="studentId" type="long">
<column name="STUTENT_ID" precision="20"/>
</property>
<many-to-one name="stutent" class="Stutent" fetch="select" insert="false" update="false">
<column name="STUTENT_ID"/>
</many-to-one>
<property name="teacherId" type="long">
<column name="TEACHER_ID" precision="20"/>
</property>
<many-to-one name="teacher" class="Teacher" insert="false" update="false" fetch="select">
<column name="TEACHER_ID"/>
</many-to-one>
</class>
</hibernate-mapping>现在问题是在保存、删除的时候,没有什么问题,中间表中的记录都已经写入了。但是在前端做更新操作时有问题,举例说明,比如stutent1中保存了teacher1,我在前端更新stutent1中为teacher2,这时没问题;但当我更新后希望的是stutent1中保存teacher1和teacher2,这时候就有问题了,它会报:
“org.springframework.orm.hibernate3.HibernateSystemException: A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance: Stutent.teacher; nested exception is org.hibernate.HibernateException: A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance: Stutent.teacher
Caused by: org.hibernate.HibernateException: A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance: Stutent.teacher”哪位高手帮我看一下好吧?多谢了!
学生表:
<hibernate-mapping default-lazy="false">
<class name="Student" table="t_stutent">
<id name="id" type="long">
<column name="ID" precision="20" scale="0"/>
<generator class="sequence">
<param name="sequence">SEQ_STUTENT</param>
</generator>
</id>
<set name="Teacher" inverse="true" lazy="false" cascade="all-delete-orphan">
<key column="STUTENT_ID"/>
<one-to-many class="StudentTeacher"/>
</set>
</class>
</hibernate-mapping>教师表:
<hibernate-mapping default-lazy="false">
<class name="Teacher" table="t_teacher">
<id name="id" type="long">
<column name="ID" precision="20" scale="0"/>
<generator class="sequence">
<param name="sequence">SEQ_TEACHER</param>
</generator>
</id>
<set name="stutent" inverse="true" lazy="false" cascade="all-delete-orphan">
<key column="TEACHER_ID"/>
<one-to-many class="StutentTeacher"/>
</set>
</class>
</hibernate-mapping>中间表(即StutentTeacher类对应的表):
<hibernate-mapping default-lazy="false">
<class name="StutentTeacher" table="t_stu_tea">
<id name="id" type="long">
<column name="ID" precision="20" scale="0"/>
<generator class="sequence">
<param name="sequence">SEQ_STU_TEA</param>
</generator>
</id>
<property name="studentId" type="long">
<column name="STUTENT_ID" precision="20"/>
</property>
<many-to-one name="stutent" class="Stutent" fetch="select" insert="false" update="false">
<column name="STUTENT_ID"/>
</many-to-one>
<property name="teacherId" type="long">
<column name="TEACHER_ID" precision="20"/>
</property>
<many-to-one name="teacher" class="Teacher" insert="false" update="false" fetch="select">
<column name="TEACHER_ID"/>
</many-to-one>
</class>
</hibernate-mapping>现在问题是在保存、删除的时候,没有什么问题,中间表中的记录都已经写入了。但是在前端做更新操作时有问题,举例说明,比如stutent1中保存了teacher1,我在前端更新stutent1中为teacher2,这时没问题;但当我更新后希望的是stutent1中保存teacher1和teacher2,这时候就有问题了,它会报:
“org.springframework.orm.hibernate3.HibernateSystemException: A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance: Stutent.teacher; nested exception is org.hibernate.HibernateException: A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance: Stutent.teacher
Caused by: org.hibernate.HibernateException: A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance: Stutent.teacher”哪位高手帮我看一下好吧?多谢了!
<many-to-one name="teacher" class="Teacher" insert="false" update="false" fetch="select">
中的
insert="false" update="false" 改下试试
http://hi.baidu.com/landor2004/blog/item/d7bc760193d995031d95839a.html
学生表的
<set name="Teacher" inverse="true" lazy="false" cascade="all-delete-orphan"> 改成teacher看映射文件基本都是生成的了,好久没看了
你想通过更新student1的teacher1为teacher2
同时数据库保存这个学生有两个老师信息?
这怎么能是更新完成的呢?更新也只是更新对应的一条啊,应该是添加吧?
楼主的业务不是太清楚……这只是我的一点儿理解!
<key>
<column name="roleid" unique="true" />
</key>
<many-to-many class="com.ipanel.pojo.Popmenus"
column="popmenusid" />
</set>权限菜单表<set name="roles" table="rolemidpopmenus" inverse="true" lazy="false">
<key>
<column name="popmenusid" not-null="true" />
</key>
<many-to-many class="com.ipanel.pojo.Role" column="roleid"/>
</set>