wordpress 中 菜单是如何存储在数据库中的
一直没有深入的了解wordpress中菜单是怎么实现的，在wordpress 中菜单很灵活，也很强大。
添加一个菜单，看看数据表中增加了什么信息
数据表中 wp_terms
select * from wp_terms;
+---------+-----------------+-----------------------------------------------+------------+
| term_id | name | slug | term_group |
+---------+-----------------+-----------------------------------------------+------------+
| 24 | 第一个菜单 | %e7%ac%ac%e4%b8%80%e4%b8%aa%e8%8f%9c%e5%8d%95 | 0 |
+---------+-----------------+-----------------------------------------------+------------+
数据表 wp_term_taxonomy
select * from wp_term_taxonomy ;
+------------------+---------+----------+-------------+--------+-------+
| term_taxonomy_id | term_id | taxonomy | description | parent | count |
+------------------+---------+----------+-------------+--------+-------+
| 24 | 24 | nav_menu | | 0 | 0 |
+------------------+---------+----------+-------------+--------+-------+
添加两个菜单项
- 一个文章链接
- 一个自定义链接
看看 wp_posts 表
select ID, post_title, post_status, post_name, post_type from wp_posts order by id desc limit 2;
+----+------------+-------------+-----------+---------------+
| ID | post_title | post_status | post_name | post_type |
+----+------------+-------------+-----------+---------------+
| 96 | wpcode | publish | wpcode | nav_menu_item |
| 95 | | publish | 95 | nav_menu_item |
+----+------------+-------------+-----------+---------------+
看看 wp_postmeta 表
select * from wp_postmeta where post_id in (95, 96) order by meta_id asc ;
+---------+---------+-----------------------------+-----------------------+
| meta_id | post_id | meta_key | meta_value |
+---------+---------+-----------------------------+-----------------------+
| 236 | 95 | _menu_item_type | post_type |
| 237 | 95 | _menu_item_menu_item_parent | 0 |
| 238 | 95 | _menu_item_object_id | 1 |
| 239 | 95 | _menu_item_object | post |
| 240 | 95 | _menu_item_target | |
| 241 | 95 | _menu_item_classes | a:1:{i:0;s:0:"";} |
| 242 | 95 | _menu_item_xfn | |
| 243 | 95 | _menu_item_url | |
| 245 | 96 | _menu_item_type | custom |
| 246 | 96 | _menu_item_menu_item_parent | 0 |
| 247 | 96 | _menu_item_object_id | 96 |
| 248 | 96 | _menu_item_object | custom |
| 249 | 96 | _menu_item_target | |
| 250 | 96 | _menu_item_classes | a:1:{i:0;s:0:"";} |
| 251 | 96 | _menu_item_xfn | |
| 252 | 96 | _menu_item_url | https://www.wpcode.cn |
+---------+---------+-----------------------------+-----------------------+
可以看到添加一个菜单 ，回字 分类表中 wp_terms 增加一项，同时在 分类方法表 wp_term_taxonomy 中也增加一项。所以在wordpress 中一个菜单本质就是一个分类。菜单的内容，就是分类的项。