插入多对多关系

Question

我有包含类别名称的“输入标签”，这意味着我在每个产品中都有多个类别，因此我创建了一个“链接表”，该链接表将存储两个表的ID。

  product table           category table        product_category table 
+---+------------+      +---+------------+    +-----------+------------+     
|id |    name    |      |id |    name    |    |product_id | category_id|
+---+------------+      +---+------------+    +-----------+------------+ 
| 1 | Cake       |      | 1 | Sweets     |    | 1         |     1      |
| 2 | Chocolate  |      | 2 | Dessert    |    | 1         |     2      |
+---+------------+      +---+------------+    | 2         |     1      |
                                              | 2         |     2      |
                                              +-----------+------------+

现在，我的问题是我不知道如何将存储为数组的数据（例如Sweets，Dessert ..）插入数据库。它总是以这个结尾：

     category table       
  +---+------------------+       
  |id |    name          |   
  +---+------------------+    
  | 1 | Sweets, Dessert  |    
  | 2 |                  |    
  +---+------------------+   

 something like that... **BUT** i want it to look like this:

      category table       
      +---+------------------+       
      |id |    name          |   
      +---+------------------+    
      | 1 | Sweets           |    
      | 2 | Dessert          |    
      +---+------------------+ 

如何在product，category和product_category表中同时插入数据？

if (mysqli_query($con, "INSERT INTO product(product_name) VALUES('$product_name')")) {

    $pk1 = mysqli_insert_id($con);
    if (mysqli_query($con, "INSERT INTO category(category_name) VALUES('$category_name')")) {

        $pk2 = mysqli_insert_id($con);
        $success = mysqli_query($con, "INSERT INTO product_category(product_id,category_id) VALUES('$pk1','$pk2')");
    }
}

if ($success) {
    echo "<script>alert('success')</script>";
} else {
    echo "error";
}

您对我有什么建议吗？我的数据库设计还可以吗？预先谢谢你。