参见法典WordPress Taxonomy 文档

WordPress 2.3用三个更灵活的分类表集取代了以前的categories、post2cat和link2cat表。

wp_terms
wp_term_relationships
wp_term_taxonomy

wp_terms- 保存有关单个术语的基本信息。

term_id bigint(20) unsigned NOT NULL auto_increment,
name varchar(200) NOT NULL default \'\',
slug varchar(200) NOT NULL default \'\',
term_group bigint(10) NOT NULL default 0,
PRIMARY KEY  (term_id),
UNIQUE KEY slug (slug),
KEY name (name)

term\\u id是术语的唯一idwp_term_taxonomy - 定义分类法-标记、类别或自定义分类法

term_taxonomy_id bigint(20) unsigned NOT NULL auto_increment,
term_id bigint(20) unsigned NOT NULL default 0,
taxonomy varchar(32) NOT NULL default \'\',
description longtext NOT NULL,
parent bigint(20) unsigned NOT NULL default 0,
count bigint(20) NOT NULL default 0,
PRIMARY KEY  (term_taxonomy_id),
UNIQUE KEY term_id_taxonomy (term_id,taxonomy),
KEY taxonomy (taxonomy)

term\\u id是术语表中术语的idwp_term_relationships - 包含WordPress对象之间的多对多关系，例如到term\\u taxonomy表中term\\u taxonomy\\u id的帖子或链接。

object_id bigint(20) unsigned NOT NULL default 0,
term_taxonomy_id bigint(20) unsigned NOT NULL default 0,
term_order int(11) NOT NULL default 0,
PRIMARY KEY  (object_id,term_taxonomy_id),
KEY term_taxonomy_id (term_taxonomy_id)

object\\u id是帖子或链接的id

term\\u顺序允许对对象的术语进行排序（请参见票证#5857）