HQL和一对多查询 [英] HQL and one-to-many queries

问题描述

  class Player {
 List< Item>库存; 
} 
 
 class物品{
列表< Enchantment>附魔; 
} 
 
 class Enchantment {
 boolean isSuperiorEnchantment; 
} 
  

我需要构建一个HQL查询，返回给我一个所有玩家列表至少有一件物品具有附魔，其中 isSuperiorEnchantment 标志设置。我不能在我的生活中想出一种方法来在HQL中表达这一点。

有什么想法？

解决方案

假设上面所有的映射都是合适的，那么您正在查找的查询是：

 从Player中选择p 
作为p 
 left加入p.inventory作为i $ b $ left加入i.enchantments作为e 
其中e.isSuperiorEnchantment = 1 
  

I have Hibernate domain objects that looks like this:

   class Player {
      List<Item> inventory;
   }

   class Item {
      List<Enchantment> enchantments;
   }

   class Enchantment {
      boolean isSuperiorEnchantment;
   }

I need to construct an HQL query that returns to me a list of all players that have at least one item with an enchantment on it that has the isSuperiorEnchantment flag set. I can't for the life of me figure out a way to express this in HQL.

Any ideas?

解决方案

Assuming the appropriate mappings on all of the above, the query you're looking for is:

select p
from Player as p
  left join p.inventory as i
  left join i.enchantments as e
where e.isSuperiorEnchantment = 1

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