title: wordpress: how is the default category "uncategorized" inserted by default in the database
body: <p>I am running a php cli script to pro grammatically post to a WordPress blog using  WordPress 3.2.1 and using only MySQL to do so. I bumped into a mystery. Even when I insert a post touching only the *_posts table, a new entry is created to *_terms_relationships. How is that done? Is there some kind of MySQL procedure somewhere to automatically do that?</p>
  
  <p>My script to insert a new post</p>
  
  <p><code>INSERT INTO wp_posts (post_title,post_content,post_name,post_date,post_date_gmt,post_modified,post_modified_gmt,post_author,post_status) VALUES (:title,:post,'post_name',now(),now(),now(),now(),1,'publish')</code></p>
  
  <p>how come this queries provokes a new row to be inserted in *_terms_relationships?</p>