最初发表在我的博客，briandouglas.ie

这是有关如何在数据库中添加按省份分组的爱尔兰县的分步指南。

第 1 步 - 省份迁移

php artisan make：迁移create_provinces_table

我们只需要一个省份的名称。

schema::create('provinces', function (blueprint $table) {
    $table->id();
    $table->string('name');
    $table->timestamps();
});

第 2 步 - 县迁移

php artisan make:migration create_counties_table

除了名称之外，县还将包含对其所属省份的引用。

schema::create('counties', function (blueprint $table) {
    $table->id();
    $table->string('name');
    $table->foreignidfor(province::class);
    $table->timestamps();
});

第 3 步 - 省份模型

php artisan make:模型省

这里我们添加 name 作为可填写的属性，并与 county 建立 hasmany 关系。

<?php namespace appmodels;

use illuminatedatabaseeloquentfactorieshasfactory;
use illuminatedatabaseeloquentmodel;
use illuminatedatabaseeloquentrelationshasmany;

class province extends model
{
    use hasfactory;

    protected $fillable = ['name'];

    public function counties(): hasmany
    {
        return $this->hasmany(county::class);
    }
}

第 4 步 - 县模型

php artisan make：模型县

这里我们添加name和province_id作为可填写属性，并与province建立belongsto关系。

<?php namespace appmodels;

use illuminatedatabaseeloquentfactorieshasfactory;
use illuminatedatabaseeloquentmodel;
use illuminatedatabaseeloquentrelationsbelongsto;

class county extends model
{
    use hasfactory;

    protected $fillable = ['name', 'province_id'];

    public function province(): belongsto
    {
        return $this->belongsto(province::class);
    }
}

第 5 步 - 省份播种者

php artisan make:seeder provinceseeder

provinceseeder 将为爱尔兰每个省创建记录，并附上相关县。

<?php namespace DatabaseSeeders;

use AppModelsProvince;
use IlluminateDatabaseConsoleSeedsWithoutModelEvents;
use IlluminateDatabaseSeeder;

class ProvinceSeeder extends Seeder
{
    /**
     * Run the database seeds.
     */
    public function run(): void
    {
        $irishCounties = [
            'Leinster' => [
                'Carlow',
                'Cavan',
                'Dublin',
                'Kildare',
                'Kilkenny',
                'Laois',
                'Longford',
                'Louth',
                'Meath',
                'Offaly',
                'Westmeath',
                'Wexford',
                'Wicklow'
            ],
            'Munster' =&gt; [
                'Clare',
                'Cork',
                'Kerry',
                'Limerick',
                'Tippperary',
                'Waterford'
            ],
            'Connacht' =&gt; [
                'Galway',
                'Leitrim',
                'Mayo',
                'Roscommon',
                'Sligo'
            ],
            'Ulster' =&gt; [
                'Antrim',
                'Armagh',
                'Cavan',
                'Derry',
                'Donegal',
                'Down',
                'Fermanagh',
                'Monaghan',
                'Tyrone'
            ]
        ];

        foreach ($irishCounties as $provinceName =&gt; $countyNames) {
            $province = Province::firstOrCreate(['name' =&gt; $provinceName]);
            foreach ($countyNames as $countyName) {
                $province-&gt;counties()-&gt;firstOrCreate(['name' =&gt; $countyName]);
            }
        }
    }
}

第 6 步 - 运行播种机

php artisan db:seed --class=provinceseeder

由于省份和县不会改变，所以播种器只需要运行一次。