从多对多关系生成层次结构

使用最佳实践

首先我建议你看看 this 托图里尔。作为使用权重生成层次结构数据的最佳实践。

而且你用拉维雄辩的关系作为它的活跃记录

//in Tag Model
public function children()
{
    return $this->hasMany('App\Models\Tag', 'parent_id');   
}

public function parent(){
     return $this->belongsTo('App\Models\Tag', 'parent_id');
}

public function nodes()
{
    return $this->hasMany('App\Models\Node', 'node_id', 'node_id');   
}

然后你就可以得到结果了

//there should be a relation for node also 
Tag::with('parent', 'children.children', 'node')->get();

一种简单的php方法

foreach ($tags as $key => $value) {
    $tagTree[$value['tag_id']] = $value;
    $tagTree[$value['tag_id']]['child'] = array();
}

foreach ($tagTree as $key => $value) {
    if ($value['parent_id'] == 0) {
        $root[$key] = &$tagTree[$key];
    } else {
        $tagTree[$value['parent_id']]['child'][$key] = &$tagTree[$key];
    }

    //here you can check if is there any node for current tag insert 
    //$tagTree[$value['parent_id']]['node'][] = ...
}