PDO-> bindParam，PDO-> bindValue和PDO-> closeCursor

Question

So far I have been using PDO->bindParam however while reading the manual I found PDO->bindValue from what I can tell PDO->bindValue passes by value where as PDO->bindParam passes by reference, is this the only difference?

$modThread = db()->prepare("UPDATE `threads` SET `modtime` = UNIX_TIMESTAMP( ) WHERE `threadid` =:id LIMIT 1");

while(something)
{
        $modThread->bindParam(':id', $thread);
        $modThread->execute();
//*******************HERE********************//
}

Again while reading the manual I found: PDO->closeCursor should I place it where marked? Is it optional/automatically called? Seems only certain drivers need it. Will calling it on a driver that doesn't need/support it cause errors? How about MySQL?

Answer 1

The 'recurring' bindParam() here is not really necessary:

$thread = 0;
$modThread->bindParam(':id', $thread);

while($thread < 20)
{
    $thread++;
    $modThread->execute(); //executing with the new value, which you couldn't do with bindValue
}

You don't need a closeCursor() when there is no resultset (i.e, only with SELECT s or procedures giving results back) , but usually I've already done a fetchAll somewhere in a previous statement / row.