- posts
-- id
-- title
-- text
 
- wp_terms
-- id
-- name
-- slug
 
- wp_term_taxonomy
-- term_taxonomy_id
-- term_id
-- taxonomy
 
- wp_term_relationships
-- object_id
-- taxonomy_id

VS.

- posts
-- id
-- title
-- text
 
- categories
-- id
-- name
-- slug
 
- relation_cat_post
-- cat_id
-- post_id
 
- tags
-- id
-- name
-- slug
 
- relation_tag_post
-- tag_id
-- post_id