下面是 city 模型 {代码...} {代码...} print 输出的数据如下关联子分类 $this->childrenCities 如果有下级分类就会有 childrenCities 如果没有 childrenCities 返回 null {代码...} {代码...} 目前是这么...

我反对递归实现。从数据库设计的角度去解决可以明显解决程序负担。关系行数据库在存储多级数据的时候。最好不要单纯做pid。id。这样的。要么加上每一层的路径。要么换结构。要是数学大神还可以用矩阵来直接计算。

咋没有回答的呢，楼主有没有解决啊~~ ^-^

php laravel eloquent 多级联动循环 laravel 视图输出 laravel 无限极分类改怎么写循环呢-PHP中文网问答

下面是 city 模型

namespace App\Model;

use Illuminate\Database\Eloquent\Model;

class City extends Model
{
    protected $table ='cities';

    public function parentCity()
    {

        return $this->belongsTo('App\Model\City', 'pid', 'id');
    }

    public function childrenCities()
    {

        return $this->hasMany('App\Model\City', 'pid', 'id');
    }
}

 /**
 * 内容资源列表数据模型仓库
 */
public function index()
{
    //$city = $this->city->all();
    $cities = City::with('childrenCities')->get();
    return $cities;

}

print 输出的数据如下关联子分类 $this->childrenCities

如果有下级分类就会有 childrenCities 如果没有 childrenCities 返回 null


[{"id":19,"pid":0,"name":"\u4e0a\u6d77\u5e02","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u9876\u7ea7\u57ce\u5e02","children_cities":[{"id":20,"pid":19,"name":"\u666e\u9640\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":21,"pid":19,"name":"\u5949\u8d24\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":22,"pid":19,"name":"\u8679\u53e3\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":23,"pid":19,"name":"\u5609\u5b9a\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":24,"pid":19,"name":"\u9759\u5b89\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":25,"pid":19,"name":"\u5362\u6e7e\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":26,"pid":19,"name":"\u95f5\u884c\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":27,"pid":19,"name":"\u6d66\u4e1c\u65b0\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":28,"pid":19,"name":"\u5b9d\u5c71\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":29,"pid":19,"name":"\u9752\u6d66\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":30,"pid":19,"name":"\u677e\u6c5f\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":31,"pid":19,"name":"\u5f90\u6c47\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":32,"pid":19,"name":"\u6768\u6d66\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":33,"pid":19,"name":"\u95f8\u5317\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":34,"pid":19,"name":"\u957f\u5b81\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"},{"id":35,"pid":19,"name":"\u9ec4\u6d66\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04"}]},{"id":20,"pid":19,"name":"\u666e\u9640\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":21,"pid":19,"name":"\u5949\u8d24\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":22,"pid":19,"name":"\u8679\u53e3\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":23,"pid":19,"name":"\u5609\u5b9a\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":24,"pid":19,"name":"\u9759\u5b89\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":25,"pid":19,"name":"\u5362\u6e7e\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":26,"pid":19,"name":"\u95f5\u884c\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":27,"pid":19,"name":"\u6d66\u4e1c\u65b0\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":28,"pid":19,"name":"\u5b9d\u5c71\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":29,"pid":19,"name":"\u9752\u6d66\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":30,"pid":19,"name":"\u677e\u6c5f\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":31,"pid":19,"name":"\u5f90\u6c47\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":32,"pid":19,"name":"\u6768\u6d66\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":33,"pid":19,"name":"\u95f8\u5317\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":34,"pid":19,"name":"\u957f\u5b81\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":35,"pid":19,"name":"\u9ec4\u6d66\u533a","tag":"shs,shanghaishi","status":0,"created_at":"2015-07-07 09:29:04","updated_at":"2015-07-07 09:29:04","pname":"\u4e0a\u6d77\u5e02","children_cities":[]},{"id":36,"pid":0,"name":"\u6c5f\u82cf\u7701","tag":"","status":0,"created_at":"2015-07-27 11:55:55","updated_at":"2015-07-27 11:55:55","pname":"\u9876\u7ea7\u57ce\u5e02","children_cities":[{"id":37,"pid":36,"name":"\u5357\u4eac\u5e02","tag":"","status":0,"created_at":"2015-07-27 11:57:48","updated_at":"2015-07-27 11:57:48"}]},{"id":37,"pid":36,"name":"\u5357\u4eac\u5e02","tag":"","status":0,"created_at":"2015-07-27 11:57:48","updated_at":"2015-07-27 11:57:48","pname":"\u6c5f\u82cf\u7701","children_cities":[{"id":38,"pid":37,"name":"\u7ebd\u533a","tag":"","status":0,"created_at":"2015-07-27 11:58:41","updated_at":"2015-07-27 11:58:41"}]},{"id":38,"pid":37,"name":"\u7ebd\u533a","tag":"","status":0,"created_at":"2015-07-27 11:58:41","updated_at":"2015-07-27 11:58:41","pname":"\u5357\u4eac\u5e02","children_cities":[]}]

/**
 * view - 视图模板 循环输出2级
 */
@foreach($cities as $key => $li)
  @if($li->pid == 0)
    <tr>              
        <td class="text-aqua">{{ $li -> name }}</td>
        <td class="text-green">{{ $li -> tag }}</td>
        <td> <a href="{{ route('admin.city.index') }}/{{ $li->id }}/edit"><i class="fa fa-fw fa-pencil" title="修改"></i></a>  </td>
    </tr>
    @foreach($li->childrenCities as $li2)
        <tr>                 
            <td class="text-aqua">  &nbsp;&nbsp; -- {{ $li2 -> name }}</td>
            <td class="text-green">{{ $li2 -> tag }}</td>
            <td> <a href="{{ route('admin.city.index') }}/{{ $li2->id }}/edit"><i class="fa fa-fw fa-pencil" title="修改"></i></a>  </td>
        </tr>
    @endforeach
  @endif
@endforeach

目前是这么写的，感觉不应该这么写输出，按照三级栏目联动循环的数据展现；

抛弃城市的上万条数据不讲；

现在就是想输出三级栏目分类；城市只是举个列子；

三级栏目改怎么在视图输出呢？反复用 foreach 循环吗

还是有其他方案输出呢？

小白，迷茫了啊；

有大神指导一下吗；怎么在视图输出呢

现在输出如下样式图