OpenJPA脏读提示
我们有以下 DAO 堆栈：
- DB2 9.7 Express-C
- OpenJPA 2.0.1
- Spring 3.0.5
- Bitronix 2.1.1
如何指定 OpenJPA 将 WITH UR sql 子句添加到查询末尾？
我已经浏览了好几天的网站和手册，它应该是这样的：
Query q = em.createQuery("select m from Magazine m where ... ");
q.setHint("openjpa.FetchPlan.ReadLockMode","WRITE");
List r = q.getResultList();
但是，唉，我一直无法找到一个可以作为 setHint() 参数和产量传递的工作 OpenJPA 属性WITH UR 结果，所以我使用 SpringJDBC 查询，不幸的是我不能再使用了。
有什么想法吗？非常感谢
We've got the following DAO stack:
- DB2 9.7 Express-C
- OpenJPA 2.0.1
- Spring 3.0.5
- Bitronix 2.1.1
How do you specify OpenJPA to add WITH UR sql clause to the end of the query?
I'd browsed sites and manuals alike for days, it should be something like this:
Query q = em.createQuery("select m from Magazine m where ... ");
q.setHint("openjpa.FetchPlan.ReadLockMode","WRITE");
List r = q.getResultList();
but alas, I've been unable to find a working OpenJPA property that would be passed as setHint() argument and yield WITH UR as result, so I use SpringJDBC queries which I unfortunately can't use any longer.
Any ideas? Thank you very much
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OpenJPA 不支持将
WITH UR子句与 JPQL 结合使用。您始终可以使用本机查询来实现此功能。OpenJPA doesn't support using the
WITH URclause with JPQL. You could always use a native query for this functionality.我现在遇到了非常相似的问题 - 似乎设置：
可以解决问题。不幸的是，源代码显示来自
org.apache.openjpa.jdbc.sql.DB2Dictionary的常量withURClause永远不会被读取。此外，如果查询不是
FOR UPDATE，OpenJPA 从不 会考虑获取计划提示。我有一个 select 语句被独占锁阻塞，它确实可以处理未提交的数据——这对 OpenJPA 来说是不行的。I'm having quite a similar problem now — it would seem that setting:
would do the trick. Unfortunately, the source code reveals that the constant
withURClausefromorg.apache.openjpa.jdbc.sql.DB2Dictionaryis never read.Additionally OpenJPA never takes into account a fetch plan hint if the query is not
FOR UPDATE. I have a select statement that gets blocked on exclusive locks and it could really work with uncommitted data — a no-go with OpenJPA.