[英]LEFT OUTER JOIN in Hibernate Inheritance
我有以下課程
@Inheritance(strategy=InheritanceType.JOINED)
Class A{
private long a_id;
private C C;
}
Class B extends A{
private D d;
}
Class C{
private long c_id;
}
Class D{
private long d_id;
private Set<B> bs;
}
B類是A類的擴展。嘗試按以下方式查詢
Criterion criterion = Restrictions.and(Restrictions.eq(
"b.c", c_instance));
Criteria c = session.createCriteria(D.class, "d")
c.createAlias("bs", "b",JoinType.LEFT_OUTER_JOIN,criterion);
c.createAlias("bs.c","c")
輸出查詢:
select d.d_id from D d left outer join B bs on d.d_id=bs.d_id and bs.c_id=2489 inner join A on bs.a_id=A.a_id inner join C A.c_id=C.c_id
我收到錯誤消息,因為c_id是B中的unknonwn列。盡管表B沒有其父表中的c_id列。 如何在此處編寫查詢以實現左外部聯接?
我猜bs是B類的集合,您正在嘗試從B類中獲取c.createAlias(“ bs.c”,“ c”)
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