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具有以下实体：

@Entity
@Table(name = "NAMES")
public class Name {
    @Id
    @GeneratedValue(generator = "increment")
    @GenericGenerator(name = "increment", strategy = "increment")
    private Long id;

    @OneToOne(mappedBy = "name", optional = true)
    private Event event;
}

@Entity
@Table(name = "EVENTS")
public class Event{
    @Id
    @GeneratedValue(generator = "increment")
    @GenericGenerator(name = "increment", strategy = "increment")
    private Long id;

    @OneToOne(optional = false)
    private Name name;
}

以及以下 JPQL 查询：

SELECT n FROM Name n JOIN n.event e WHERE e=:uref

查询通过以下方式执行：

String queryString = "SELECT n FROM Name n JOIN n.event e WHERE e=:uref";
List<Name> result = entityManager.createQuery(queryString, Name.class)
            .setParameter("uref", userRef).getResultList();

我收到以下错误：

Hibernate: 
    select
        name0_.id as id1_ 
    from
        NAMES name0_ 
    inner join
        EVENTS event1_ 
            on name0_.id=event1_.name_id 
    where
        event1_.id=?
1-Aug-2012 3:18:31 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 90012, SQLState: 90012
1-Aug-2012 3:18:31 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: Parameter "#1" is not set; SQL statement:
select name0_.id as id1_ from NAMES name0_ inner join EVENTS event1_ on name0_.id=event1_.name_id where event1_.id=? [90012-168]

为什么加入不起作用？

奇怪的是，这个非常相似的查询有效：

SELECT e.name FROM Event e WHERE e=:uref
Hibernate: 
    select
        name1_.id as id1_ 
    from
        EVENTS event0_ 
    inner join
        NAMES name1_ 
            on event0_.name_id=name1_.id 
    where
        event0_.id=?

这是用 Hibernate 4.1.5.SP1 和 4.1.0.Final 尝试过的

注意：第一个查询在 OpenJPA 中有效

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