我已经这样写了HQL查询:
SELECT a FROM A a LEFT JOIN a.b where ...
Hibernate生成这样的sql查询:
SELECT a FROM A a LEFT JOIN a.b where a.b_id = b.id(+)
但是当我写这样的东西:
SELECT a FROM where a.b.id > 5
它生成SQL:
SELECT a.* FROM A b cross join B b where b.id > 5
因此,当我结合使用这种方法时,我会收到Oracle错误:
SQL Error: 25156, SQLState: 99999 ORA-25156: old style outer join (+) cannot be used with ANSI joins
那么有没有办法对Hibernate说我只想接收一种类型的查询(旧样式或新样式)?
更新: 结合我的意思是这样的HQL查询:
SELECT alarm FROM Alarm as a LEFT JOIN alarm.madeBy as user where user.name = 'George' and a.source.name = 'UFO'
因此,在这里我指定 Alarm 应该通过LEFT JOIN 与 User 连接,而不是指定如何将 Alarm 与 Source 连接,因此Hibernate将其与Cross Join连接。
和SQL查询将是这样的:
FROM Alarms a, Users u cross join Sources s where a.user_id = u.user_id(+) and a.source_id = s.source_id and u.name = 'George' and s.name = 'UFO'
为了获得更多理解,我将添加警报实体的小示例:
@Entity @Table(name = 'Alarms') public class Alarm { @Id private BigDecimial id; @ManyToOne @JoinColumn(name = "user_id") private User madeBy; @ManyToOne @JoinColumn(name = "source_id") private Source source; }
因此,解决此问题的方法是将hibernate的方言设置为org.hibernate.dialect.Oracle9Dialect
<property name="hibernate.dialect">org.hibernate.dialect.Oracle9Dialect</property>