php laravel fasih berbilang peringkat gelung pautan laravel paparan keluaran laravel pengelasan tak terhingga cara menulis gelung

Question

Berikut ialah model bandar

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;

}

Output data mengikut

cetak adalah seperti berikut: Subkategori persatuan $this->childrenCities

Jika terdapat kategori peringkat rendah, akan ada 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

Beginilah ia ditulis pada masa ini, tetapi saya rasa ia tidak sepatutnya ditulis seperti ini Output dipaparkan mengikut data kitaran pautan lajur tiga peringkat

Tinggalkan puluhan ribu data di bandar itu

Sekarang saya hanya mahu mengeluarkan klasifikasi lajur tiga peringkat;

Bagaimana untuk mengeluarkan lajur peringkat ketiga dalam paparan? Adakah anda menggunakan gelung foreach berulang kali?

Adakah terdapat sebarang penyelesaian lain untuk output?

Xiaobai, saya keliru;

Bolehkah sesiapa memberi saya panduan Bagaimana untuk mengeluarkan dalam paparan

Sekarang keluarkan gambarajah gaya berikut

Answer 1

Anda perlu melaksanakannya secara rekursif.

Answer 2

Saya menentang pelaksanaan rekursif. Menyelesaikannya dari perspektif reka bentuk pangkalan data jelas dapat menyelesaikan beban program.
Pangkalan data baris perhubungan menyimpan data berbilang peringkat. Sebaiknya jangan buat pid sahaja. id. macam ni.
Atau tambah laluan setiap lapisan. Atau ubah struktur. Jika anda seorang ahli matematik, anda juga boleh menggunakan matriks untuk mengira secara langsung.

Answer 3

Kenapa tiada jawapan?