java Hibernate 错误 IllegalArgumentException：要遍历的节点不能为空
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Hibernate Error IllegalArgumentException: node to traverse cannot be null
提问by Kevin Meredith
My DELETEquery is failing.
我的DELETE查询失败。
Here's my code:
这是我的代码：
String q = "SELECT p.id FROM Person p, DomainGroup g WHERE
p member of g.coordinators" + " AND g.id = :groupId
AND p.id = :personId";
List<Long> test = getEntityManager()
.createQuery(q).setParameter("groupId", followingId)
.setParameter("personId", followerId).getResultList();
log.debug("test = " + test);
String deleteGroupCoordinatorQuery =
"DELETE FROM Person p, DomainGroup g WHERE p member
of g.coordinators" + " AND g.id = :groupId
AND p.id = :personId";
List<Long> test = getEntityManager()
.createQuery(deleteGroupCoordinatorQuery).setParameter
("groupId", followingId)
.setParameter("personId", followerId).executeUpdate();
output:
输出：
test = [1,2,3]
2012-10-26 13:44:56,437 ERROR org.company.commons.server.service.ServiceActionController - Error occurred performing transaction. java.lang.IllegalArgumentException: node to traverse cannot be null!
at org.hibernate.hql.ast.util.NodeTraverser.traverseDepthFirst(NodeTraverser.java:55)
at org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:280)
at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:182)
at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136)
回答by Steve Ebersole
You define multiple "query roots" (Person pand DomainGroup g), but a DELETE query can have only one such root.
您定义了多个“查询根”（Person p和DomainGroup g），但 DELETE 查询只能有一个这样的根。
You want something like:
你想要这样的东西：
delete Person p
where p.id in (
select c.id
from DomainGroup g
join g.coordinators c
where g.id = :groupId
and c.id = :personId
)
or
或者
delete Person p
where p.id = :personId
and p.id in (
select c.id
from DomainGroup g
join g.coordinators c
where g.id = :groupId
)
回答by Roman C
If you don't use on delete cascadefeature then you should remove all references to the object before deleting it.
如果您不使用on delete cascade功能，那么您应该在删除之前删除对对象的所有引用。
