wp_set_wpdb_vars() WordPress Function

function wp_set_wpdb_vars() {
	global $wpdb, $table_prefix;
	if ( ! empty( $wpdb->error ) ) {
		dead_db();
	}

	$wpdb->field_types = array(
		'post_author'      => '%d',
		'post_parent'      => '%d',
		'menu_order'       => '%d',
		'term_id'          => '%d',
		'term_group'       => '%d',
		'term_taxonomy_id' => '%d',
		'parent'           => '%d',
		'count'            => '%d',
		'object_id'        => '%d',
		'term_order'       => '%d',
		'ID'               => '%d',
		'comment_ID'       => '%d',
		'comment_post_ID'  => '%d',
		'comment_parent'   => '%d',
		'user_id'          => '%d',
		'link_id'          => '%d',
		'link_owner'       => '%d',
		'link_rating'      => '%d',
		'option_id'        => '%d',
		'blog_id'          => '%d',
		'meta_id'          => '%d',
		'post_id'          => '%d',
		'user_status'      => '%d',
		'umeta_id'         => '%d',
		'comment_karma'    => '%d',
		'comment_count'    => '%d',
		// Multisite:
		'active'           => '%d',
		'cat_id'           => '%d',
		'deleted'          => '%d',
		'lang_id'          => '%d',
		'mature'           => '%d',
		'public'           => '%d',
		'site_id'          => '%d',
		'spam'             => '%d',
	);

	$prefix = $wpdb->set_prefix( $table_prefix );

	if ( is_wp_error( $prefix ) ) {
		wp_load_translations_early();
		wp_die(
			sprintf(
				/* translators: 1: $table_prefix, 2: wp-config.php */
				__( '<strong>Error</strong>: %1$s in %2$s can only contain numbers, letters, and underscores.' ),
				'<code>$table_prefix</code>',
				'<code>wp-config.php</code>'
			)
		);
	}
}