nhibernate 获取整棵树
我需要帮助使用 nhibernate 3.0 从数据库获取树层次结构，
QueryOver.Of<Enterprise>(() => entAlias)
.JoinAlias(() => entAlias.ChildEntities, () => childEntityAllias, JoinType.LeftOuterJoin)
.TransformUsing(new DistinctRootEntityResultTransformer())
我只得到图形的两个级别（父级及其子级），而不是子级的子级等。
如果我尝试获取叶子的父级，情况也是如此。我只得到叶子的父级，而不是叶子的父级的父级的父级。其中级别 = n。
何做这种类型的查询。无论是 Icriteria、linq、HQL 还是其他。
I need help fetching tree hierarchy from db using nhibernate 3.0
QueryOver.Of<Enterprise>(() => entAlias)
.JoinAlias(() => entAlias.ChildEntities, () => childEntityAllias, JoinType.LeftOuterJoin)
.TransformUsing(new DistinctRootEntityResultTransformer())
I am getting only the two level of the graph (parent and its childrens) but not the childrens of children etc.
The same is if I try to fetch parents of the leaf. I get only the parent of the leaf, but not parent of the parent of the parent... of the leaf. where level = n.
Ho to do this type of query. no mather if Icriteria, linq, HQL or else.
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您可以使用批量大小来更有效地获取子项。
子项仍然由单独的查询加载（您不应该再将它们加入到查询中），但总是一次加载 20 个。将“N+1”变为“N/20+1”，通常效果很好。这个解决方案的优点是你不需要在查询中关心。
您还可以批量加载父级：
如果可能，它会批量加载与企业的多对一关系。
如果您需要更多优化，请考虑添加对根（最顶层父级）的引用。然后，您可以通过一个简单的查询加载根的所有子项。缺点是你需要关心这个引用，它是一个冗余，也可能很难维护。
You could use batch-size to fetch the children more efficiently.
Children are still loaded by separate queries (you shouldn't join them in the query anymore), but always 20 at once. To turns "N+1" to "N/20+1" which usually performs very good. The advantage of this solution is that you don't need to care about in your queries.
You could also load parents in batches:
It loads many-to-one relations to Enterprises in batches if possible.
If you need even more optimization, consider to add a reference to the root (the top most parent). Then you can load all the children of a root in one easy query. The disadvantage is that you need to care about this reference, it is a redundancy which could also be hard to maintain.
如果你真的想获取所有内容（尽管我不确定你为什么要这样做），那么在 NHibernate 中禁用延迟加载（从而启用急切加载）。
If you really want to fetch everything (although I'm not sure why you would do such a thing) then disable lazy loading (thus enabling eager loading) in NHibernate.