多态OneToMany图像-产品关系，如何知道哪些图像是哪些？

Question

对于个人项目，我正在尝试使用 laravel 创建一个网上商店。 我有一个产品表和一个图像表，它们具有一对多多态关系。 有些产品是不同的，可能只需要一个图像，而其他产品则需要能够有多个。 我正在努力寻找一种方法来知道哪个图像是哪个。例如，一张图片可能是产品的缩略图，另一张可能是产品一部分的图片等。我应该创建一个新表 image_types 并将 id 存储在我的 images 表中，还是这无效？

产品表

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateProductsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('products', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
            $table->text('description')->nullable();
            $table->decimal('stock', 8, 2)->nullable();
            $table->decimal('price', 8, 2)->nullable();
            $table->unsignedBigInteger('product_category_id');
            $table->foreign('product_category_id')->references('id')->on('product_categories')->onDelete('cascade');
            $table->unsignedBigInteger('account_type_id');
            $table->foreign('account_type_id')->references('id')->on('account_types')->onDelete('cascade');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('products');
    }
}

图片表

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateImagesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('images', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('url');
            $table->morphs('imageable');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('images');
    }
}

Answer 1

要为一个产品保存多张图片，您可以将一列中的图片网址保存为数组字符串 为此，您必须在 Image 模型中转换 url 列，如下所示：

protected $casts = [
    'url' => 'array' // when set the url it convert to string and when get data it convert to array
];

然后，当您要保存图像 url 时，为任何类型的图像设置密钥，例如设置缩略图和原始图像，请执行以下操作：

$urlArray = [];
$urlArray['thumbnail'] = $thumbnailUrl;
$urlArray['original'] = $originalUrl;

这是一个简单的例子，你可以用这种方式为任何类型的图像设置键，即使你想为缩略图保存几个大小，你可以执行以下操作：

$urlArray['thumbnail']['240'] = $thumbnailUrlLow; // or set key ['thumbnailLow']
$urlArray['thumbnail']['320'] = $thumbnailUrlMed;
$urlArray['thumbnail']['480'] = $thumbnailUrlHigh;

要获取产品的缩略图网址，请执行以下操作：

$image->url['thumbnail']['320']

获取原始图片大小：

$iamge->url['original'];

您可以为任何类型的产品图像设置很多键。

不要忘记为目标列定义protected $casts，并设置转换为数组的时间。

Answer 2

# images migration file
public function up()
{
    Schema::create('images', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->unsignedBigInteger('product_id');
        $table->string('url');
        // Maybe add the following column if you really need to be able
        // to tell the difference between what is and isn't a thumbnail.
        // $table->enum('type', ['thumbnail', 'other']);

        $table->foreign('product_id')->references('id')->on('products');
    });
}

# Image model
class Image extends Model
{
    public function product()
    {
        // an Image belongs to a Product, using the foreign key 'product_id'
        return $this->belongsTo(Product::class, 'product_id');
    }
}

# Product model
class Product extends Model
{
    public function images()
    {
        // a Product has one or many images (Image), using the foreign key 'product_id'
        return $this->hasMany(Image::class, 'product_id');
    }
}

$product = Product::find($product_id);
// get a collection of all the Product's images
$product->images

$image = Image::find($image_id);
// get THE product this image belongs to
$image->product

更多阅读：

• https://laravel.com/docs/6.x/eloquent-relationships#one-to-many
• https://laravel.com/docs/6.x/eloquent-relationships#one-to-many-inverse
• https://laravel.com/docs/6.x/eloquent-relationships#inserting-and-updating-related-models