WordPress at a glance
function is not described

upgrade_100() WP 1.0.0

Execute changes made in WordPress 1.0.

  • Global. wpdb. $wpdb WordPress database abstraction object.

No Hooks.

Return

Nothing (null).

Usage

upgrade_100();

Code of upgrade 100: wp-admin/includes/upgrade.php VER 5.0.3

<?php
function upgrade_100() {
	global $wpdb;

	// Get the title and ID of every post, post_name to check if it already has a value
	$posts = $wpdb->get_results("SELECT ID, post_title, post_name FROM $wpdb->posts WHERE post_name = ''");
	if ($posts) {
		foreach ($posts as $post) {
			if ('' == $post->post_name) {
				$newtitle = sanitize_title($post->post_title);
				$wpdb->query( $wpdb->prepare("UPDATE $wpdb->posts SET post_name = %s WHERE ID = %d", $newtitle, $post->ID) );
			}
		}
	}

	$categories = $wpdb->get_results("SELECT cat_ID, cat_name, category_nicename FROM $wpdb->categories");
	foreach ($categories as $category) {
		if ('' == $category->category_nicename) {
			$newtitle = sanitize_title($category->cat_name);
			$wpdb->update( $wpdb->categories, array('category_nicename' => $newtitle), array('cat_ID' => $category->cat_ID) );
		}
	}

	$sql = "UPDATE $wpdb->options
		SET option_value = REPLACE(option_value, 'wp-links/links-images/', 'wp-images/links/')
		WHERE option_name LIKE %s
		AND option_value LIKE %s";
	$wpdb->query( $wpdb->prepare( $sql, $wpdb->esc_like( 'links_rating_image' ) . '%', $wpdb->esc_like( 'wp-links/links-images/' ) . '%' ) );

	$done_ids = $wpdb->get_results("SELECT DISTINCT post_id FROM $wpdb->post2cat");
	if ($done_ids) :
		$done_posts = array();
		foreach ($done_ids as $done_id) :
			$done_posts[] = $done_id->post_id;
		endforeach;
		$catwhere = ' AND ID NOT IN (' . implode(',', $done_posts) . ')';
	else:
		$catwhere = '';
	endif;

	$allposts = $wpdb->get_results("SELECT ID, post_category FROM $wpdb->posts WHERE post_category != '0' $catwhere");
	if ($allposts) :
		foreach ($allposts as $post) {
			// Check to see if it's already been imported
			$cat = $wpdb->get_row( $wpdb->prepare("SELECT * FROM $wpdb->post2cat WHERE post_id = %d AND category_id = %d", $post->ID, $post->post_category) );
			if (!$cat && 0 != $post->post_category) { // If there's no result
				$wpdb->insert( $wpdb->post2cat, array('post_id' => $post->ID, 'category_id' => $post->post_category) );
			}
		}
	endif;
}