来自数据库中数组的 Laravel 关系

Question

我想知道你是否可以帮助建立 laravel 关系。我会尽力解释。

我有两张桌子：

警报

Schema::create('alerts', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->integer('user_id');
            $table->float('price_low')->nullable();
            $table->float('price_high')->nullable();
            $table->json('conditions')->nullable();
            $table->softDeletes();
            $table->timestamps();
        });

条件

DB::table('conditions')->insert([
            ['condition_value' => 'New'],
            ['condition_value' => 'Second Hand'],
            ['condition_value' => 'Ex Demo'],
]);

条件字段'conditions'存储一个这样的数组：

[{"condition_id": 1}, {"condition_id": 2}]

我正在尝试定义一种关系，以便可以执行以下操作：

$alerts = Alerts::with(['condition'])->where('user_id', $request->user()->id)->get();

我的警报模型如下所示：

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

class Alerts extends Model
{
    protected $casts = [
        'conditions' => 'array'
    ];
    

    public function user(){
        return $this->hasOne('App\User', 'id', 'user_id');
    }

    public function condition(){
        return $this->hasMany('App\Condition', 'id', 'conditions[condition_id]');
    }
}

但没有返回任何内容，我正在努力在 Laravel 文档中找到答案。

Answer 1

警报模型

Schema::create('alerts', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->integer('user_id');
            $table->float('price_low')->nullable();
            $table->float('price_high')->nullable();
            $table->unsignedBigInteger('conditions')->nullable();
            $table->foreign('conditions')->references('id')->on('conditions');
            $table->softDeletes();
            $table->timestamps();
        });

条件模型

Schema::create('conditions', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('condition_value')->nullable();
            $table->softDeletes();
            $table->timestamps();
        });

在警报表中为一个 user_id 插入多个记录，例如一个用户 ID 具有多个条件，例如：

user_id: 1 条件：1

user_id: 1 条件：2

user_id: 1 条件：3

Answer 2

你无法得到你需要的关系的条件

public function getConditionsAttribute($conditions)
    {
        return App\Condition::whereIn('id',collect($conditions)->pluck('condition_id'))->get();
    }

它会动态获取你的数据，这将使它像逻辑一样

Answer 3

为什么不将警报和条件之间的关系建模为多对多？

我会使用以下迁移：

Schema::create('alerts', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->unsignedBigInteger('user_id'); // I assume your users table uses a bigIncrements for id
    $table->decimal('price_low')->nullable(); // Do not use FLOAT type for prices as is can cause rounding issues.
    $table->decimal('price_high')->nullable();
    $table->softDeletes();
    $table->timestamps();

    $table->foreign('user_id')->references('id')->on('users');
});

Schema::create('alert_condition', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->unsignedBigInteger('alert_id');
    $table->unsignedBigInteger('condition_id');
    $table->timestamps();

    $table->foreign('alert_id')->references('id')->on('alerts');
    $table->foreign('condition_id')->references('id')->on('conditions');
});

Schema::create('conditions', function (Blueprint $table) {
    $table->bigIncrements('id');
    $table->string('value');
    $table->timestamps();
});

插入您现在必须使用的条件：

DB::table('conditions')->insert([
    ['value' => 'New'],
    ['value' => 'Second Hand'],
    ['value' => 'Ex Demo'],
]);

您需要注意的唯一额外事项是，警报和条件之间的每个关联都将是 alert_condition 数据透视表中的一条记录，其中包含您要连接的两个模型的外键。

这可以通过多种方式完成。要坚持以前的 conditions 插入，您可以使用：

DB::table('alert_condition')->insert([
    ['alert_id' => 1, 'condition_id' => 1],
    ['alert_id' => 1, 'condition_id' => 2],
    ['alert_id' => 2, 'condition_id' => 1],
    // ...
]);

然后我会使用以下模型：

警报模型

<?php

namespace App;

use Illuminate\Database\Eloquent\Relations\Pivot;
use Illuminate\Database\Eloquent\SoftDeletes;

class Alerts extends Pivot
{
    use SoftDeletes;

    public function user()
    {
        return $this->belongsTo(User::class);
    }

    public function conditions()
    {
        return $this->belongsToMany(Condition::class);
    }
}

条件模型

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Condition extends Model
{
    public function alerts()
    {
        return $this->belongsToMany(Alert::class);
    }
}

然后在你的控制器或任何你需要的地方你可以像这样查询：

// Assuming your authentication works with the User model and that model
// has a correct hasMany alerts() relationship.
$user = Auth::user();

// This would print out all the alerts for the current logged in user
// and each alert will contain the conditions values associated to that alert.
dump($user->alerts()->with('conditions')->get());

// If you also need to keep the user with its data, just eager load the relations
dump($user->load('alerts.conditions'));