MySQL类别列表vs独立类别表

我正在创建一个博客网站，它可以让你为博客分配一个类别。原来的表是这样的:

+----+----------+-------+---------+
| ID | CATEGORY | TITLE | ARTICLE |
+----+----------+-------+---------+
| 01 | cars     | Title | Article |
| 02 | cars     | Title | Article |
| 03 | sport    | Title | Article |
| 04 | music    | Title | Article |
| 05 | music    | Title | Article |
+----+----------+-------+---------+

如您所见，类别是一个写好的属性。主题是有一个单独的类别列表，我创建它看起来像:

+-------------------+
| CAT_ID | CATEGORY |
+--    --+----------+
| 01     | cars     |
| 02     | sport    |
| 03     | music    |
+--------+----------+

将原表修改为:

+----+--------------------+----------+-------+---------+-----------+
| ID | BELONGS_TO_BLOG_ID | CATEGORY | TITLE | ARTICLE | AUTHOR_ID |
+----+--------------------+----------+-------+---------+-----------+
| 01 | 01                 | 01       | Title | Article | 01        |
| 02 | 01                 | 01       | Title | Article | 01        |
| 03 | 02                 | 02       | Title | Article | 02        |
| 04 | 02                 | 03       | Title | Article | 03        |
| 05 | 02                 | 03       | Title | Article | 03        |
+----+--------------------+----------+-------+---------+-----------+

现在，如果我想删除01类别的cars，而不是删除它(因为显然有2篇文章在这个类别中)，我可能会将其更改为unnassigned。所以这里没有问题，但如果我要删除music (03)并将其更改为unnassigned，我最终会与ID的01 & 03被取消分配。所以现在当我运行搜索unnassigned文章时，它应该返回4，我只会看到2或一个错误。

拥有原始表，当有人更改类别cars时，他们只是UPDATE记录不是更好吗?

ALTER TABLE items
ADD FOREIGN KEY (category)
REFERENCES category(categoryTable)

$sql="select count(*) as cnt  from items where category=CATEGORY_TO_BE_DELETED";
if(mysql_query('cnt')>0) //means it has some items 
  //do not delete or throw some error
else
  //delete