<!-- Collection of code snippets by Arne Vajhøj -->
<!-- posted to eksperten.dk, usenet and other places (2002-now) -->
<?php
function get_connection() {
	$con = new mysqli('localhost', 'root', '', 'Test');
	if(mysqli_connect_errno()) {
		die(mysqli_connect_error());
	}
	return $con;
}

function insert($con, $stmt, $un, $pw) {
	$stmt->bind_param('ss', $un, $pw);	
	$stmt->execute() or die(mysqli_error($con));
}

function setup() {
	$con = get_connection();
	$con->query('CREATE TABLE unpw (un VARCHAR(32), pw VARCHAR(256), PRIMARY KEY(un))') or die(mysqli_error($con));
	$stmt = $con->prepare('INSERT INTO unpw VALUES(?,?)') or die(mysqli_error($con));
	insert($con, $stmt, 'A', 'Not updated');
	insert($con, $stmt, 'B', 'Not updated');
	insert($con, $stmt, 'C', 'Not updated');
	insert($con, $stmt, 'D', 'Updated');
	$stmt->close();
	$con->close();
}

function dump() {
	$con = get_connection();
	$rs = $con->query('SELECT un,pw FROM unpw') or die(mysqli_error($con));
	while($row = $rs->fetch_array(MYSQLI_ASSOC)) {
		$un = $row['un'];
		$pw = $row['pw'];
		echo "$un $pw\r\n";
	}
	$con->close();
}

function teardown() {
	$con = get_connection();
	$con->query('DROP TABLE unpw') or die(mysqli_error($con));
	$con->close();
}

function superhash($pw) {
	return 'Updated';
}

function update() {
	$selcon = get_connection();
	$updcon = get_connection();
	$selstmt = $selcon->prepare('SELECT un,pw FROM unpw WHERE pw = ?') or die(mysqli_error($selcon));
	$updstmt = $updcon->prepare('UPDATE unpw SET pw = ? WHERE un = ?') or die(mysqli_error($updcon));
	$targetpw = 'Not updated'; 
	$selstmt->bind_param('s', $targetpw);
	$selstmt->execute() or die(mysqli_error($selcon));
	$rs = $selstmt->get_result();
	while($row = $rs->fetch_array(MYSQLI_ASSOC)) {
		$un = $row['un'];
		$pw = $row['pw'];
		$newpw = superhash($pw);
		$updstmt->bind_param('ss', $newpw, $un);
		$updstmt->execute() or die(mysqli_error($updcon));
	}
	$updstmt->close();
	$selstmt->close();
	$updcon->close();
	$selcon->close();
}

setup();
dump();
update();
dump();
teardown();

?>