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我具有低於類LEFT OUTER在休眠JOIN繼承
@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;
}
這裏B類是延伸類A.試圖如下查詢
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
我得到一個錯誤,因爲c_id在B中是未知列。雖然表B是沒有其父表具有c_id列。我如何寫一個查詢來實現左外連接?
是的,C是不是B類的屬性,但是它可以繼承自A類而不發生。這是我的問題 –