org.hibernate.QueryException：非法尝试解引用集合 [英] org.hibernate.QueryException: illegal attempt to dereference collection

问题描述

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

但它显示

  org.hibernate.QueryException：非法尝试取消引用collection 
 [billdetail0_.bill_no .billProductSet]带有元素属性引用[product] 
 [select count（*）from iland.hbm.BillDetails as bd where bd.billProductSet.product.id = 1001 and bd.client.id = 1] 
在org.hibernate.hql.ast.tree.DotNode $ 1.buildIllegalCollectionDereferenceException（DotNode.java:68）
在org.hibernate.hql.ast.tree.DotNode.checkLhsIsNotCollection（DotNode.java:558）
  

解决方案

billProductSet 是集合。
因此，它没有名为 product 的属性。

Product 是元素的一个属性收集。

您可以通过加入集合来解决问题，而不是解除引用：

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

I am trying following hql query to execute

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

But it is showing

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)

解决方案

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

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