Proof of Concept for bulk-updating posts with membership protection (if the post didn't previously have protection)

pmpro-bulk-update.php

<?php
/*
Plugin Name: PMPro Bulk Update
Plugin URI: http://www.paidmembershipspro.com/wp/pmpro-customizations/
Description: Allow updating all posts to a membership level
Version: .1
Author: Thomas Sjolshage <thomas@eighty20results.com>
Author URI: http://www.eighty20results.com/thomas-sjolshagen/
*/

function pmprobu_update_all_posts() {

	error_log("Trigger update of posts to set membership level(s)");

	global $wpdb;

	$nSQL = $wpdb->prepare("
		SELECT p.ID
		FROM {$wpdb->posts} AS p
		WHERE ((post_type = 'post') AND (p.ID NOT IN (SELECT page_id FROM {$wpdb->pmpro_memberships_pages})))
	");

	$not_protected = $wpdb->get_col($nSQL);

	if (!empty( $not_protected)) {

		$sql = array();

		$sql[] = "
			INSERT INTO {$wpdb->pmpro_memberships_pages} ( membership_id, modified, page_id )	  
			SELECT 1,  NOW(), p.ID
			FROM {$wpdb->posts} AS p
			WHERE (p.post_type = 'post') AND (p.ID NOT IN (" . implode(",", $not_protected) . "))";

		$sql[] = "
			INSERT INTO {$wpdb->pmpro_memberships_pages} ( membership_id, modified, page_id )	  
			SELECT 2,  NOW(), p.ID
			FROM {$wpdb->posts} AS p
			WHERE (p.post_type = 'post') AND (p.ID NOT IN (" . implode(",", $not_protected) . "))";

		$sql[] = "
			INSERT INTO {$wpdb->pmpro_memberships_pages} ( membership_id, modified, page_id )	  
			SELECT 3,  NOW(), p.ID
			FROM {$wpdb->posts} AS p
			WHERE (p.post_type = 'post') AND (p.ID NOT IN (" . implode(",", $not_protected) . "))";

		foreach( $sql as $s ) {

			error_log("Wanting to run query: {$s}");

			if (false === $wpdb->query($s)) {

				wp_die("Failure while updating the page/protection information! Error: {$wpdb->last_error}" );

			} else {
				error_log("Successfully updated Database w/new post protection");
			}
		}
	}
}

register_activation_hook( __FILE__, 'pmprobu_update_all_posts' );