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我有两个表:研究和用户研究,研究有userResearches列表使用@OneToMany映射到userResearch。我试图执行一个简单的HQL查询为什么这个简单的hql查询不起作用?未分类SQLException
from Research r inner join r.userResearches ur where ur.user=:user
,并得到此异常:
Hibernate operation: could not execute query; uncategorized SQLException for SQL [select...]; SQL state [24000]; error code [0]; Operation requires a scrollable ResultSet, but this ResultSet is FORWARD_ONLY.; nested exception is org.postgresql.util.PSQLException: Operation requires a scrollable ResultSet, but this ResultSet is FORWARD_ONLY.
什么能是什么原因? 实体映射正确,一切工作正常,我可以使用标准API检索两个实体。
@Entity
public class UserResearch extends ManagedEntity {
@ManyToOne
@JoinColumn(name = "research_id")
private Research research;
@Entity
public class Research extends ManagedEntity {
@OneToMany(mappedBy = "research")
private Set<UserResearch> userResearches = new HashSet<UserResearch>(0);
您是否尝试过使用其他Collection接口,例如'List'?这个问题可能不在查询本身,因为它看起来很合理,但我不能把它放在手边。 – kostja