如何更新 Laravel 关系表

Question

有两种型号：

Product 和 Product_Images

class Product extends Eloquent { 
    protected $guarded = [];
    public $timestamps = true;

    public function images(){
        return $this->hasMany('product_image');
    }

    public function brand(){
        return $this->belongsTo('brand');
    }
}

class Product_Image extends Eloquent { 
    protected $table = 'product_images';
    protected $guarded = [];

    public function images(){
        return $this->hasMany('product_image');
    }
}

我可以更新或插入数据到这个模型

$product = new Product;
$product->title = $data['title'];
$product->alias = $data['alias'];
$product->short_description = $data['short_description'];
$product->price = $data['price'];
$product->brand_id = $data['brand_id'];
$product->description = $data['description'];
$product->published = 1;
$product->save();
foreach($data['images'] as $k => $v){
    if($data['main'] == $k){
        $product->images()->save(
            new Product_Image(['image' => $v,'main' => 1])
        );  
    }else{
        $product->images()->save(
            new Product_Image(['image' => $v,'main' => 0])
        );
    }
}

但是当用户尝试编辑产品时，用户可能会删除现有图像并尝试添加新图像并发送表单。我应该按照哪种方式更新图像关系。我应该删除与产品相关的所有图像并创建新图像吗？这对我来说似乎是不好的做法，有什么最好的吗？

Answer 1

首先你的关系是错误的，我认为你与产品和图像有一对多的关系

应该是这样的

public function images(){
    return $this->hasMany('product_image');
}

public function product()
{
    return $this->belongsTo(Product::class);//import your product class with use
}

你也错误地定义了你的关系。在您的关系中，您可以选择定义类，在某些情况下您可以传递外键和本地键以及表名，请参阅Defining Relationships

这应该是

public function images(){
    return $this->hasMany('product_image');
}
public function brand(){
    return $this->belongsTo('brand');
}

这个

public function images(){
    return $this->hasMany(Product_Image::class);//import class
}
public function brand(){
    return $this->belongsTo(Brand::class);//import Brand class
}

你也可以在这里简化你的代码

       if($data['main'] == $k){
            $product->images()->save(
                new Product_Image(['image' => $v,'main' => 1])
            );  
        }else{
            $product->images()->save(
                new Product_Image(['image' => $v,'main' => 0])
            );
        }


        $product->images()->save(
            new Product_Image(['image' => $v,'main' => (int)($data['main'] == $k)])
        );