Laravel 数据透视表间关联：方案优劣及模型实现方法？

1. 数据库迁移（添加people_place_id字段） #

先生成迁移文件：

php artisan make:migration add_people_place_id_to_people_things_table

打开生成的迁移文件，编写字段添加逻辑：

public function up()
{
    Schema::table('people_thing', function (Blueprint $table) {
        $table->unsignedBigInteger('people_place_id')->nullable();
        $table->foreign('people_place_id')->references('id')->on('people_place')->onDelete('cascade');
    });
}

public function down()
{
    Schema::table('people_thing', function (Blueprint $table) {
        $table->dropForeign(['people_place_id']);
        $table->dropColumn('people_place_id');
    });
}

执行迁移生效：

php artisan migrate

2. 模型关联定义 #

PeoplePlace 模型 #

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class PeoplePlace extends Model
{
    protected $table = 'people_place';

    // 关联所属用户
    public function person()
    {
        return $this->belongsTo(People::class, 'people_id');
    }

    // 关联对应地点
    public function place()
    {
        return $this->belongsTo(Places::class, 'place_id');
    }

    // 关联该记录下的所有物品
    public function things()
    {
        return $this->hasMany(PeopleThing::class, 'people_place_id');
    }
}

PeopleThing 模型 #

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class PeopleThing extends Model
{
    protected $table = 'people_thing';

    // 关联对应的用户-地点记录
    public function peoplePlace()
    {
        return $this->belongsTo(PeoplePlace::class, 'people_place_id');
    }

    // 关联物品本身
    public function thing()
    {
        return $this->belongsTo(Things::class, 'thing_id');
    }

    // 间接关联所属用户
    public function person()
    {
        return $this->hasOneThrough(People::class, PeoplePlace::class, 'id', 'id', 'people_place_id', 'people_id');
    }
}

People 模型 #

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class People extends Model
{
    protected $table = 'people';

    // 关联用户的所有地点记录
    public function peoplePlaces()
    {
        return $this->hasMany(PeoplePlace::class, 'people_id');
    }

    // 间接关联用户的所有物品
    public function things()
    {
        return $this->hasManyThrough(PeopleThing::class, PeoplePlace::class, 'people_id', 'people_place_id', 'id', 'id');
    }
}

Things 模型 #

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Things extends Model
{
    protected $table = 'things';

    // 关联物品的所有持有记录
    public function peopleThings()
    {
        return $this->hasMany(PeopleThing::class, 'thing_id');
    }
}

3. 常用操作示例 #

• 获取用户某地点记录下的所有物品

$targetPlaceRecord = People::find(1)->peoplePlaces()->where('place_id', 5)->first();
$itemsInPlace = $targetPlaceRecord->things;

• 获取某物品的所在地点及所属用户

$itemRecord = PeopleThing::find(3);
$placeInfo = $itemRecord->peoplePlace->place;
$ownerInfo = $itemRecord->peoplePlace->person;

• 创建关联特定地点记录的物品

$existingPlaceRecord = PeoplePlace::find(2);
$existingPlaceRecord->things()->create([
    'thing_id' => 7,
    // 其他people_thing表的自定义字段
]);

内容的提问来源于stack exchange，提问作者CptMisery