magento2.2.3 根据产品ID获取栏目名称的正确调用方式

• 根据product_id 获取 category_ids : 
  

      /**
       * @param $product_id
       * @return array
       */
      public function mc_getCategoryIds($product_id)
      {
  //       +++ get product the category id
          $registry = $this->mc_C['product'];
          $getObj = $this->mc_get_obj($registry);
          /**
           * @var \Magento\Catalog\Model\Product $getObj
           * \Magento\Catalog\Model\Product
           */
          $product = $getObj->load($product_id);
  
          /**
           * @var \Magento\Catalog\Model\Product $product
           * \Magento\Catalog\Model\Product
           */
  
          return $product->getCategoryIds();
      }

   

• 获取 category_name ：
  

  /**
       * @param $product_id
       * @return mixed
       */
      public function mc_getCategoryName($product_id)
      {
          $cats = $this->mc_getCategoryIds($product_id);
          if(count($cats) ){
              $firstCategoryId = $cats[(count($cats)-1)];
              $registry = $this->mc_C['category'];
              $getObj = $this->mc_get_obj($registry);
  
              /**
               * @var \Magento\Catalog\Model\CategoryFactory $getObj
               */
              $_category = $getObj->create();
              /**
               * @var \Magento\Catalog\Model\CategoryFactory $_category
               */
              $data = $_category->load($firstCategoryId);
              /**
               * @var \Magento\Catalog\Model\CategoryFactory $data
               */
              return $data->getName();
          }
          return 0;
      }

   

以上简单的调用了栏目的名称。

FAQ:

1，如果使用不正确的 CategoryFactory 类 ： 

• 're_category_c'=>\Magento\Catalog\Model\ResourceModel\Category\CollectionFactory::class,//fixme This class \Magento\Catalog\Model\ResourceModel\Category\Collection

• 're_category_f'=>\Magento\Catalog\Model\ResourceModel\CategoryFactory::class,//fixme This class\Magento\Catalog\Model\ResourceModel\Category

• 're_category'=>\Magento\Catalog\Model\ResourceModel\Category::class,//fixme This  Catalog category model

　　正确的是：\Magento\Catalog\Model\CategoryFactory

　　ResourceModel 与 Model 的区别：

 

 

Models : Models are where your main business logic should be handled and is a single instance of an object. The model will use the resource model to talk to the database and get/set data for it on save() and load().

Resource Model : A resource model is where your main C.R.U.D happens (Create, Read, Updateand delete). The resource model shouldn’t contain business logic however it will talk to the adapters and basically talk to the database.

 

 

2，如果使用不正确的通用SQL ： 

　　SQL: 

select value from catalog_product_entity_varchar left join eav_attribute on
    eav_attribute.attribute_id = catalog_product_entity_varchar.attribute_id
where
    eav_attribute.attribute_code='name' and 
    catalog_product_entity_varchar.entity_id=2082

　　CODE:

$_connection = $this->mc_get_obj(\Magento\Framework\App\ResourceConnection::class);//get class
            $db_connection = $_connection->getConnection(\Magento\Framework\App\ResourceConnection::DEFAULT_CONNECTION);//connection
            $category = $db_connection->fetchAll('select * from '.'`catalog_product_entity_varchar` '.'left join '.'`eav_attribute` '.'on '.
                '`eav_attribute`.'.'`attribute_id`='.'`catalog_product_entity_varchar`.'.'`attribute_id` '.
                'where '.'`eav_attribute`.'.'`attribute_code`='.'"name" '.'and '. '`catalog_product_entity_varchar`.'.'`entity_id`='.$vi['product_id']);

            var_dump($category[0]['value']);die;

　　

　　正确的SQL: 
　　

SELECT 
  e.entity_id AS product_id
  , e.type_id AS product_type
  , e.sku,
  (
    SELECT
      GROUP_CONCAT(DISTINCT(cv.value))
    FROM 
      catalog_category_entity_varchar AS cv, catalog_category_product AS at_category_id 
    WHERE
      at_category_id.category_id = cv.entity_id
      AND (at_category_id.product_id = e.entity_id) 
      AND cv.attribute_id = 41 and cv.store_id = 0
  ) AS category_name 
FROM catalog_product_entity AS e where e.entity_id=2082;