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我可以使用HQL加载属性吗?

eager-loading hql select nhibernate

dommer · 技术社区 · 15 年前

我正在尝试解决如何在以下HQL查询中加载客户:

select order.Customer
from Order as order
where order.Id in
(
  select itemId
  from BadItem as badItem
  where (badItemType = :itemType) and (badItem.Date >= :yesterday)
)

订单和客户之间通常存在多对一的关系。

我想做的是在查询中,而不是映射中,如果可能的话-就像在“连接获取…”

有什么想法吗?

1 回复 | 直到 15 年前

Alexander Torstling 15 年前

select customer
from BadItem as badItem
join fetch badItem.Order as order
left join fetch order.Customer as customer 
where (badItemType = :itemType) and (badItem.Date >= :yesterday)

如果BadItem与Order无关,则需要添加BadItem和Order之间的关系,或者使用 inner join 附加条件(使用备选方案2时注意性能)。

备选方案:

select customer
from Order as order
join fetch order.Customer as customer
where order.Id in
(
  select itemId
  from BadItem as badItem
  where (badItemType = :itemType) and (badItem.Date >= :yesterday)
)

编辑:

关于:

select customer
from Order as order
join fetch order.Customer customer
join fetch customer.orders 
where order.Id in
(
  select itemId
  from BadItem as badItem
  where (badItemType = :itemType) and (badItem.Date >= :yesterday)
)

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