Source

File: wp-admin/includes/upgrade.php

function install_global_terms() {
		global $wpdb, $charset_collate;
		$ms_queries = "
CREATE TABLE $wpdb->sitecategories (
  cat_ID bigint(20) NOT NULL auto_increment,
  cat_name varchar(55) NOT NULL default '',
  category_nicename varchar(200) NOT NULL default '',
  last_updated timestamp NOT NULL,
  PRIMARY KEY  (cat_ID),
  KEY category_nicename (category_nicename),
  KEY last_updated (last_updated)
) $charset_collate;
";
		// Now create tables.
		dbDelta( $ms_queries );
	}