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Hibernate Collection链接(Hibernate Collection chaining)

 我有两个实体 
 

University   
   courses

Course
   students

 

 我想访问大学里的所有学生。 我尝试了以下查询 
 

select u.courses.students from university u

 

 我有以下例外。 
 

org.hibernate.QueryException: illegal attempt to dereference collection [university0_.id.courses] with element property reference [students] [ select u.courses.students from com.socialsite.persistence.University u  ]
    at org.hibernate.hql.ast.tree.DotNode$1.buildIllegalCollectionDereferenceException(DotNode.java:46)
  .....

 

 任何人都能解释这有什么问题吗？ 

I have two Entities
 

University   
   courses

Course
   students

 

i want to access all the students in a university. I tried the following query
 

select u.courses.students from university u

 

i got the following exception.
 

org.hibernate.QueryException: illegal attempt to dereference collection [university0_.id.courses] with element property reference [students] [ select u.courses.students from com.socialsite.persistence.University u  ]
    at org.hibernate.hql.ast.tree.DotNode$1.buildIllegalCollectionDereferenceException(DotNode.java:46)
  .....

 

can anyone explain what is wrong with this?

原文：https://stackoverflow.com/questions/2550885
更新时间：2022-04-24 09:04

最满意答案

 您无法使用实时SDK版本执行此操作，此功能已添加到当前正在开发中的CARTO Mobile SDK 4.1.0中。 
 

 查看更多： https ： //github.com/CartoDB/mobile-sdk/issues/88 
 

 更新：SDK 4.1.0 alpha版本现在可以从nuget （适用于iOS或Android ）获取，只需在nuget包装载器中启用“预发布”版本，然后选择4.1.0-alpha-8或更新版本的CartoMobileSDK 。 

You cannot do this with live SDK version, this feature is added to CARTO Mobile SDK 4.1.0, currently in development. 
 

See more: https://github.com/CartoDB/mobile-sdk/issues/88 
 

Update: SDK 4.1.0 alpha version can now be taken from nuget (for iOS or Android), just enable "Pre-release" versions in nuget package loader and pick 4.1.0-alpha-8 or newer for CartoMobileSDK.

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