magento2.2.3 way to get the right to call the name of the column based on product ID

• According to acquire category_ids product_id: 
  
  

      /**
       * @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();
      }

  View Code

   

• Get 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;
      }

  View Code

   

More than simply call the name of the column.

FAQ:

1, if you use an incorrect CategoryFactory categories : 

• '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

　　Is correct: \ Magento \ Cataog \ Model \ CategoryFactory

　　ResourceModel and Model difference:

 

 

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, if you use incorrect generic 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;

　　

　　Correct 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;