Symfony \\ Component \\ Debug \\ Exception \\ FatalThrowableError（E_ERROR）找不到類“購物車”

Question

在產品上調用刪除功能時，出現上述錯誤。 如果我注釋掉分離數據透視表的那一行，則delete函數可以正常工作，但是在刪除產品時，我也要刪除數據透視表中的所有條目。 有人知道為什么會這樣嗎？

數據庫已成功遷移並播種。

數據透視表遷移：

<?php

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

class CreateOrderProductTable extends Migration
{
/**
 * Run the migrations.
 *
 * @return void
 */
public function up()
{
    Schema::create('order_product', function (Blueprint $table) {
        $table->integer('order_id');
        $table->integer('product_id');
        $table->float('price');
        $table->integer('amount');
        $table->primary(array('order_id', 'product_id'));
        $table->timestamps();
    });
}

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

產品型號：

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Product extends Model
{
protected $fillable = ['name', 'price', 'stock', 'short_description', 'long_description'];

public function orders() {
    return $this->belongsToMany('App\Order', 'order_product', 'product_id', 'order_id');
}

public function carts() {
    return $this->belongsToMany('App\Cart', 'cart_product', 'product_id', 'cart_id');
}
}

刪除功能：

public function destroy($id)
{
    if ($this->validateID($id)) {
        $product = Product::find($id);
        //$product->carts()->detach(); --THE PROBLEMATIC LINE
        Product::destroy($id);
    }
    Session::flash('success', $product->name.' has been succesfully deleted.');
    return redirect()->to('/products');
}

Answer 1

您沒有在belongsToMany關系中提供完整的名稱空間。

大概是這樣的（除非您有模型的子文件夾）：

public function orders() {
    return $this->belongsToMany('App\Order', 'order_product', 'product_id', 'order_id');
}

public function carts() {
    return $this->belongsToMany('App\Cart', 'cart_product', 'product_id', 'cart_id');
}

另外，我建議將其添加到數據透視遷移中：

Schema::create('order_product', function (Blueprint $table) {
    // Also, you would need to make `order_id` and `product_id` unsigned,
    // assuming your other `id` columns are `autoincrement` (which are unsigned by default)
    $table->integer('order_id')->unsigned();
    $table->integer('product_id')->unsigned();
    $table->float('price');
    $table->integer('amount');
    $table->primary(array('order_id', 'product_id'));
    $table->timestamps();

    // Adds foreign key to orders
    $table->foreign('order_id')
        ->references('id')
        ->on('orders')
        // Automatically deletes the pivot, when related order is deleted
        ->onDelete('cascade');

    // Adds foreign key to products
    $table->foreign('product_id')
        ->references('id')
        ->on('products')
        // Automatically deletes the pivot, when related cart is deleted
        ->onDelete('cascade');
});

此外，遷移的down()部分中的表與up()部分中的實際表名不匹配。