异常: 取消引用收集的非法尝试

我尝试按照 hql 查询执行

SELECT count(*)
FROM BillDetails as bd
WHERE bd.billProductSet.product.id = 1002
AND bd.client.id                 = 1

但它已经显现出来了

org.hibernate.QueryException: illegal attempt to dereference collection
[billdetail0_.bill_no.billProductSet] with element property reference [product]
[select count(*) from iland.hbm.BillDetails as bd where bd.billProductSet.product.id=1001 and bd.client.id=1]
at org.hibernate.hql.ast.tree.DotNode$1.buildIllegalCollectionDereferenceException(DotNode.java:68)
at org.hibernate.hql.ast.tree.DotNode.checkLhsIsNotCollection(DotNode.java:558)

66282 次浏览

小开

最佳答案

billProductSet is a Collection. As such, it does not have an attribute named product.

Product is an attribute of the elements of this Collection.

You can fix the issue by joining the collection instead of dereferencing it:

SELECT count(*)
FROM BillDetails        bd
JOIN bd.billProductSet  bps
WHERE bd.client.id       = 1
AND bps.product.id     = 1002

小开

because billProduct is one to many mapping and there is many billProduct entity from one BillDetails entity you can't dereference it in query.you must join BillDetails model to billProduct and filter result with where cluase.