违反完整性约束：1452 可填充也不起作用

Question

我有一个数据透视表 category_product 我想在其中存储 product_id category_id

它在 phpmyadmin 中可以正常工作，但在 laravel 中不起作用

我尝试了可填充但仍然无法正常工作

PDOException::("SQLSTATE[23000]: 完整性约束违规：1452 无法添加或更新子项 行：外键约束失败 (new.category_product, CONSTRAINT category_product_category_id_foreign FOREIGN KEY (category_id) REFERENCES categories (id) ON DELETE CASCADE)")

Category.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Category extends Model
{
    protected $fillable = ['parent_id'];

    public function childs() {
        return $this->hasMany('App\Category', 'parent_id');
    }

    public function products()
    {
        return $this->belongsToMany('App\Product');
    }
}


Product.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Product extends Model
{
    public function presentPrice() {
        return "Rs ".number_format($this->price);
    }

    public function categories() {
        return $this->belongsToMany('App\Category');
    }
}

CategoryProduct.php 

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class CategoryProduct extends Model
{
    protected $table = 'category_product';

    protected $fillable = ['product_id', 'category_id'];
}

2018_08_15_224031_create_category_product_table.php

<?php

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

class CreateCategoryProductTable extends Migration
{

        /**
         * Run the migrations.
         *
         * @return void
         */
        public function up()
        {
            Schema::create('category_product', function (Blueprint $table) {
                $table->increments('id');

                $table->integer('product_id')->unsigned()->nullable();
                $table->foreign('product_id')->references('id')
                      ->on('products')->onDelete('cascade');

                $table->integer('category_id')->unsigned()->nullable();
                $table->foreign('category_id')->references('id')
                      ->on('categories')->onDelete('cascade');
                $table->timestamps();
            });
        }

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

ProductTableSeeder.php

<?php

use App\Product;
use Illuminate\Database\Seeder;

class ProductsTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        // Laptops
        for ($i=1; $i <= 7; $i++) {
            Product::create([
                'name' => 'Laptop '.$i,
                'slug' => 'laptop-'.$i,
                'details' => [13,14,15][array_rand([13,14,15])] . ' inch, ' . [1, 2, 3][array_rand([1, 2, 3])] .' TB SSD, 32GB RAM',
                'price' => rand(30000, 60000),
                'description' =>'Lorem '. $i . ' ipsum dolor sit amet, consectetur adipisicing elit. Ipsum temporibus iusto ipsa, asperiores voluptas unde aspernatur praesentium in? Aliquam, dolore!',
                'image' => 'products/dummy/laptop-'.$i.'.jpg',
                'images' => '["products\/dummy\/laptop-2.jpg","products\/dummy\/laptop-3.jpg","products\/dummy\/laptop-4.jpg"]',
            ])->categories()->attach(4);
        }

        // Phones
        for ($i = 1; $i <= 7; $i++) {
            Product::create([
                'name' => 'Phone ' . $i,
                'slug' => 'phone-' . $i,
                'details' => [16, 32, 64][array_rand([16, 32, 64])] . 'GB, 5.' . [7, 8, 9][array_rand([7, 8, 9])] . ' inch screen, 4GHz Quad Core',
                'price' => rand(20000, 50000),
                'description' => 'Lorem ' . $i . ' ipsum dolor sit amet, consectetur adipisicing elit. Ipsum temporibus iusto ipsa, asperiores voluptas unde aspernatur praesentium in? Aliquam, dolore!',
                'image' => 'products/dummy/phone-'.$i.'.jpg',
                'images' => '["products\/dummy\/phone-2.jpg","products\/dummy\/phone-3.jpg","products\/dummy\/phone-4.jpg"]',
            ])->categories()->attach(2);
        }

        // Cameras
        for ($i = 1; $i <= 11; $i++) {
            Product::create([
                'name' => 'Camera ' . $i,
                'slug' => 'camera-' . $i,
                'details' => 'Full Frame DSLR, with 18-55mm kit lens.',
                'price' => rand(40000, 150000),
                'description' => 'Lorem ' . $i . ' ipsum dolor sit amet, consectetur adipisicing elit. Ipsum temporibus iusto ipsa, asperiores voluptas unde aspernatur praesentium in? Aliquam, dolore!',
                'image' => 'products/dummy/camera-'.$i.'.jpg',
                'images' => '["products\/dummy\/camera-3.jpg","products\/dummy\/camera-4.jpg","products\/dummy\/camera-5.jpg"]',
            ])->categories()->attach(5);
        }

                // Select random entries to be featured
        Product::whereIn('id', [1, 6, 8, 12, 15, 18, 20, 21, 23,22, 24, 13, 10])->update(['featured' => true]);

    }
}

Answer 1

您想同步您的产品和类别，但是 mysql 找不到给定的 category_id。

可能您忘记在类别表上创建这些行。