Hibernate 和 GAE 中的树（分层）结构
我想在 Hibernate（以及 GAE）中对分层数据进行建模。
实体结构类似于如下：
class Node<T>
{
Long id;
T nodeValue;
Node<T> parent;
List<Node<T>> children;
}
如果有必要（我认为会有必要），我可以使用 JPA 注释。
应支持以下功能：
添加新根（数据库中可以有多棵树 -。可以不用这个，如果这会导致无法启动设计（通过使用一些“看不见的曾祖父根节点”）parent = null）- 向任何父节点添加新节点
- 删除节点及其整个子树结构
- 更新节点（例如，更改父/子等）
- 能够在树中自上而下和自下而上移动
- 最重要的是......给定一个
id，能够获取特定节点然后向上移动（祖先路径）/向下（子路径）
更多信息（更新）
从逻辑上讲，这就是我想要实现的目标：
- 在表中拥有一个简单的类别列表。这些类别彼此没有关系
- 有一个表将为这些类别创建多个“层次结构集”。
为什么我需要它们？
我正在创建一个应用程序，其中可以将文档提交到这些类别。
然而，每个用户对相同类别可能有不同的看法。例如，我可能想创建一个层次结构 Company ->部门->人力资源->世界->亚洲->印度 而其他人可能想看看公司 ->世界->亚洲->印度->部门->人力资源部。
任何对这种结构建模的帮助都会很棒。
I want to model a hierarchical data in Hibernate (and also in GAE).
The entity structure is similar to as below:
class Node<T>
{
Long id;
T nodeValue;
Node<T> parent;
List<Node<T>> children;
}
I am fine with using JPA annotations, if that's necessary (which I think will be).
The following features should be supportable:
Adding a new root (there can be multiple trees in the database - with. Can do without this, if this can result in a non-starter to design (by using some "invisible great-grandfather root node")parent = null)- Adding a new node to any parent
- Deleting a node and it's entire sub-tree structure
- Updating a node (say, changing parent/children etc)
- Ability to travel top-down as well as bottom-up within a tree
- And most importantly... Given an
id, ability to fetch the specific node and then travel upwards (ancestor-path) / downwards (children-path)
More Info (Updates)
Here's what I logically want to achieve:
- Have a flat list of categories in a table. These categories have no relation with each other
- Have a table that will create multiple "set of hierarchies" for these categories.
Why do I need them?
I am creating an application wherein documents can be submitted to these categories.
However, each user may have a different view point to the same categories. For example, I may want to create a hierachy Company -> Departments -> HR -> World -> Asia -> India whereas somebody else may want to see Company -> World -> Asia -> India -> Departments -> HR.
Any help to model this structure will be great.
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评论（1）
你想要的可能是这样的（来自 Hibernate 的测试套件）：
https://github.com/hibernate/hibernate-orm/blob/master/hibernate-core/src/test/java/org/hibernate/ test/annotations/manytoone/Node.java
但如果没有任何具体问题，很难回答......
What you want is probably something like this (from Hibernate's test suite):
https://github.com/hibernate/hibernate-orm/blob/master/hibernate-core/src/test/java/org/hibernate/test/annotations/manytoone/Node.java
But without any specific question, it's hard to answer...