GORM 中的树结构(grails) [英] Tree structure in GORM (grails)

问题描述

我正在尝试在 GORM 中定义树结构.这是我的模型:

I'm trying to define a tree structure in GORM. Here is my model:

class Tree {
    String name
    Level rootLevel

    static hasOne = [rootLevel: Level]
    static hasMany = [levels: Level]
    static mappedBy = [levels:"parentTree"]
}

class Level {
    String name
    Tree parentTree
    Level parentLevel
    Set<Level> subLevels

    static belongsTo = [parentTree: Tree]
    static hasMany = [subLevels: Level]
}

插入似乎工作正常，但是当我无法加载具有多个级别和子级别的树时.我想我错过了一些关系:- 树应该有一个对 rootLevel 的引用(以及可选的所有子级别)- 一个关卡应该有一个对它的父关卡、它的子关卡和全局父树的引用

Insertion seems to work fine, but when I can't load a Tree with many levels and sublevels. I guess I missed something in the relations: - the Tree should have a reference to the rootLevel (and optionally to all sublevels) - a Level should have a reference to its parent level, its sublevels and the global parent Tree

你能指出我正确的方向来获得这样的树结构吗?谢谢

Could you point me out the right direction to get a tree structure like this ? Thanks

推荐答案

我最终得到了这个解决方案(感谢一位朋友):

I ended up with this solution (thanks to a friend):

class Tree {
   String name
   Level rootLevel

   static hasMany = [levels: Level]
   static mappedBy = [rootLevel: "parentTree", levels: "owningTree"]

   static constraints = {rootLevel(nullable: true)}
}

和

class Level {
   String name
   Tree parentTree
   Tree owningTree
   Level parentLevel
   Set<Level> subLevels

   static belongsTo = [owningTree: Tree, parentLevel: Level]
   static hasMany = [subLevels: Level]
   static mappedBy = [parentTree: "rootLevel", owningTree: "levels", subLevels: "parentLevel"]

   static constraints = {
       parentTree(nullable: true)
       parentLevel(nullable: true)
   }
}

我遗漏了 Tree 和 Level 之间的两个关系(owningTree 和 parentTree)以及一些有助于休眠的mappedBy 配置.

I was missing the two relations between Tree and Level (owningTree and parentTree) and some mappedBy configuration to help hibernate.

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