Laravel模型关系问题

Question

I'm trying to retrieve all product categories with all their respective products, one product belongs to one product category and one product category can have many products.

When I retrieve productCategories I get the following error:

 Illuminate \ Database \ QueryException (42S22)
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'products.product_category_id' in 'where clause' (SQL: select * from `products` where `products`.`product_category_id` in (1, 2, 3))

This is my migrations file for product and categories:

<?php


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


class ProductsAndCategories extends Migration
{
    public function up()
    {
        //CREATE PRODUCT CATEGORIES TABLE
        Schema::create('productcategories', function (Blueprint $table) {
            $table->increments('id');
            $table->string('title');
            $table->string('description')->nullable();
            $table->string('image')->nullable();
            $table->timestamps();
        });

        //  CREATE PRODUCTS TABLE
        Schema::create('products', function (Blueprint $table) {
            $table->increments('id');
            $table->unsignedInteger('productcategory_id')->index();
            $table->foreign('productcategory_id')->references('id')->on('productcategories');
            $table->string('title');
            $table->string('description')->nullable();
            $table->string('body')->default('');
            $table->string('image')->nullable()->default(config('globals.dummy_image'));
            $table->boolean('isVisible')->default(true);
            $table->integer('stockLeft')->default(0);
            $table->decimal('halfPrice', 5,2)->default(0.00);
            $table->decimal('fullPrice', 5,2)->default(0.00);
            $table->decimal('finalPrice', 5,2)->default(0.00);
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('products');
        Schema::dropIfExists('productcategories');
    }
}

And my two related models:

Product:

<?php
namespace App\Models;


use Illuminate\Database\Eloquent\Model;


class Product extends Model
{
    protected $table = 'products';

    public function productcategory()
    {
        return $this->belongsTo('App\Models\ProductCategory', 'productcategory_id');
    }
}

ProductCategory:

<?php
namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class ProductCategory extends Model
{
    protected $table = 'productcategories';

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

Answer 1

First of all you need to define right keyword for hasMany relation. Change HasMany to hasMany() ; and Model look like this:-

<?php
    namespace App\Models;
    use Illuminate\Database\Eloquent\Model;
    class Product extends Model
    {
          protected $table = 'products';
          protected $primary_key = 'product_id';
          public function productcategory()
          {
               return $this->belongsTo('App\Models\ProductCategory', 'productcategory_id');
          } 
    }

and second model look like this: -

<?php
    namespace App\Models;
    use Illuminate\Database\Eloquent\Model;
    class ProductCategory extends Model
    {
         protected $table = 'productcategories';
         protected $primary_key = 'id';
         public function products()
         {
              return $this->HasMany('App\Models\Product', 'id');
         }
    }

and Query will be look like this: -

$product_list = Product::with('productcategory')->get();

this query will give you all records and category of particular record.