我有一个多字段唯一约束的持久类。但定义的唯一约束对于我来说是不够的，因为在这些字段中，不相等但相似的值也是唯一的。
我实现了一个 checkUniqueConstraint 方法。 在添加和更新DAO类的方法中，我在调用 checkUniqueConstraint 之前添加或更新持久化对象。
checkUniqueConstraint 方法只是运行一个SELECT查询来找到类似于输入的对象，并且抛出一个检查Exception在哪里找到一些。
public class PersistClassDao { public void checkUniqueConstraint（PersistClass persistObject）throws DuplicateEntityException { / ** *创建查询字符串，查找类似的持久对象输入参数。 ** / 尝试{ PersistClass result =（PersistClass）query.uniqueResult（）; if（result！= null&&（persistObject.getId（）== null || persistObject.getId（）！= result.getId（）））{ throw new DuplicateEntityException（exceptionMessage， ）; } } catch（NonUniqueResultException e）{ throw new DuplicateEntityException（exceptionMessage）; $ b public long add（/ *新的persistObject * /的字段）抛出DuplicateEntityException { //创建persistObject的transisent实例 PersistClass newObject = getPersistClass（/ * new persistObject * /的字段）; checkUniqueConstraint（newObject）; 尝试{ getCurrentSession（）。save（newObject）; getCurrentSession（）。flush（）; 返回newObject.getId（）; } catch（ConstraintViolationException e）{ throw new DuplicateEntityException（）; $我有一个transactionl服务mehod添加和另一个更新。当我运行我的测试时，
但是真的是一个org.hibernate.exception。 ConstraintViolationException抛出checkUniqueConstraint !!
为什么？
解决方案问题必须出现在 FlushMode 中。 Hibernate默认在执行查询之前刷新实体，请参阅 http ：//docs.jboss/hibernate/core/3.5/javadocs/org/hibernate/FlushMode.html#AUTO 。
您必须有部分初始化新实体，将它们与会话绑定的实体相关联，然后尝试执行查询。 Hibernate会话在查询之前执行flush操作，并以ConstraintViolationException失败，这是正常的。
解决方案：
I have a Persistent Class with multi-field unique constraint on it. But defined unique constraint is not sufficient for me because on one those field non-equal but similar values are unique too.
I implement a checkUniqueConstraint method. In add and update methods of DAO class, I call checkUniqueConstraint before adding or updating persist object.
checkUniqueConstraint method just run a SELECT query to find object similar to input and throw a check Exception where find some ones.
public class PersistClassDao { public void checkUniqueConstraint(PersistClass persistObject) throws DuplicateEntityException { /** * creating a query string that find persist objects similar to input parameter. **/ try { PersistClass result = (PersistClass) query.uniqueResult(); if(result != null && (persistObject.getId() == null || persistObject.getId() != result.getId())){ throw new DuplicateEntityException(exceptionMessage, ""); } } catch (NonUniqueResultException e) { throw new DuplicateEntityException(exceptionMessage); } } public long add(/* field of new persistObject*/) throws DuplicateEntityException { //creates a transisent instance of persistObject PersistClass newObject = getPersistClass(/* field of new persistObject*/); checkUniqueConstraint(newObject); try { getCurrentSession().save(newObject); getCurrentSession().flush(); return newObject.getId(); } catch (ConstraintViolationException e) { throw new DuplicateEntityException(); } }I have a transactionl service mehod for add and another for update.
When I run my test that
- First add 2 persistObjects (through service method).
- Then update one (through service method) them so that be similar to the other
- I expect that DuplicatException be thrown
But really a org.hibernate.exception. ConstraintViolationException thrown through checkUniqueConstraint!!
Why?
解决方案The problem must be in FlushMode. Hibernate by default flushes entities before executing queries, see docs.jboss/hibernate/core/3.5/javadocs/org/hibernate/FlushMode.html#AUTO.
You must have partially initialized new entities, associated them with the session-bounded ones and now try to do the query. Hibernate session executes flush just before the query and fails with ConstraintViolationException, which is OK.
Solution:
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