WordPress at a glance
function is not described

upgrade_300() WP 3.0.0

Execute changes made in WordPress 3.0.

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

No Hooks.

Return

Nothing (null).

Usage

upgrade_300();

Code of upgrade 300: wp-admin/includes/upgrade.php VER 5.0.3

<?php
function upgrade_300() {
	global $wp_current_db_version, $wpdb;

	if ( $wp_current_db_version < 15093 )
		populate_roles_300();

	if ( $wp_current_db_version < 14139 && is_multisite() && is_main_site() && ! defined( 'MULTISITE' ) && get_site_option( 'siteurl' ) === false )
		add_site_option( 'siteurl', '' );

	// 3.0 screen options key name changes.
	if ( wp_should_upgrade_global_tables() ) {
		$sql = "DELETE FROM $wpdb->usermeta
			WHERE meta_key LIKE %s
			OR meta_key LIKE %s
			OR meta_key LIKE %s
			OR meta_key LIKE %s
			OR meta_key LIKE %s
			OR meta_key LIKE %s
			OR meta_key = 'manageedittagscolumnshidden'
			OR meta_key = 'managecategoriescolumnshidden'
			OR meta_key = 'manageedit-tagscolumnshidden'
			OR meta_key = 'manageeditcolumnshidden'
			OR meta_key = 'categories_per_page'
			OR meta_key = 'edit_tags_per_page'";
		$prefix = $wpdb->esc_like( $wpdb->base_prefix );
		$wpdb->query( $wpdb->prepare( $sql,
			$prefix . '%' . $wpdb->esc_like( 'meta-box-hidden' ) . '%',
			$prefix . '%' . $wpdb->esc_like( 'closedpostboxes' ) . '%',
			$prefix . '%' . $wpdb->esc_like( 'manage-'	   ) . '%' . $wpdb->esc_like( '-columns-hidden' ) . '%',
			$prefix . '%' . $wpdb->esc_like( 'meta-box-order'  ) . '%',
			$prefix . '%' . $wpdb->esc_like( 'metaboxorder'    ) . '%',
			$prefix . '%' . $wpdb->esc_like( 'screen_layout'   ) . '%'
		) );
	}

}