具有两个主键的 Laravel 模型更新 [重复]

我正在尝试更新有两个主键的模型。

模型

namespace App;

use Illuminate\Database\Eloquent\Model;

class Inventory extends Model
{
    /**
     * The table associated with the model.
     */
    protected $table = 'inventories';

    /**
     * Indicates model primary keys.
     */
    protected $primaryKey = ['user_id', 'stock_id'];
...

移民

Schema::create('inventories', function (Blueprint $table) {
    $table->integer('user_id')->unsigned();
    $table->integer('stock_id')->unsigned();
    $table->bigInteger('quantity');

    $table->primary(['user_id', 'stock_id']);

    $table->foreign('user_id')->references('id')->on('users')
        ->onUpdate('restrict')
        ->onDelete('cascade');
    $table->foreign('stock_id')->references('id')->on('stocks')
        ->onUpdate('restrict')
        ->onDelete('cascade');
});

这是应该更新库存模型的代码，但它没有。

$inventory = Inventory::where('user_id', $user->id)->where('stock_id', $order->stock->id)->first();
$inventory->quantity += $order->quantity;
$inventory->save();

我收到此错误：

Illegal offset type

我还尝试使用 updateOrCreate() 方法。它不起作用（我得到同样的错误）。

谁能告诉我应该如何更新具有两个主键的模型？

我已经遇到过这个问题好几次了。您需要覆盖一些属性：

protected $primaryKey = ['user_id', 'stock_id'];
public $incrementing = false;

和方法（credit https://github.com/laravel/framework/issues/5355#issuecomment-161376267):

/**
 * Set the keys for a save update query.
 *
 * @param  \Illuminate\Database\Eloquent\Builder  $query
 * @return \Illuminate\Database\Eloquent\Builder
 */
protected function setKeysForSaveQuery(Builder $query)
{
    $keys = $this->getKeyName();
    if(!is_array($keys)){
        return parent::setKeysForSaveQuery($query);
    }

    foreach($keys as $keyName){
        $query->where($keyName, '=', $this->getKeyForSaveQuery($keyName));
    }

    return $query;
}

/**
 * Get the primary key value for a save query.
 *
 * @param mixed $keyName
 * @return mixed
 */
protected function getKeyForSaveQuery($keyName = null)
{
    if(is_null($keyName)){
        $keyName = $this->getKeyName();
    }

    if (isset($this->original[$keyName])) {
        return $this->original[$keyName];
    }

    return $this->getAttribute($keyName);
}

请记住，此代码需要引用 Eloquent Builder 类

use Illuminate\Database\Eloquent\Builder;

我建议将这些方法放在HasCompositePrimaryKey特质让你可以use它适用于任何需要它的模型。