'PDOException' with message 'SQLSTATE[HY000]: General error: 2014 Cannot execute queries while other unbuffered queries are active

Question

I know this question has been asked many times, but the commonly-accepted answers didn\'t help me. But quite by accident I stumbled on an answer.

Here\'s the setup: I h

Answer 1

Trigger can be created via PDO::exec() even when PDO::ATTR_EMULATE_PREPARES = false:

<?php
$db = new PDO ($cnstring, $user, $pwd);
$db->setAttribute (PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$db->setAttribute (PDO::ATTR_EMULATE_PREPARES, false);
$db->setAttribute (PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true);

$db->exec("CREATE TRIGGER `CirclesClosureSync` AFTER INSERT ON Circles
FOR EACH ROW BEGIN
    INSERT INTO CirclesClosure (ancestor, descendant) 
    SELECT ancestor, NEW.ID from CirclesClosure WHERE descendant=NEW.Parent;
    INSERT INTO CirclesClosure (ancestor, descendant) values (NEW.ID, NEW.ID);
END;");

Answer 2

Took a bit of fiddling, but I found that when I took the ATTR_EMULATE_PREPARES=false out (the default is to emulate), it worked:

<?php
$db = new PDO ($cnstring, $user, $pwd);
$db->setAttribute (PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
//$db->setAttribute (PDO::ATTR_EMULATE_PREPARES, false);
$db->setAttribute (PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true);

$st = $db->query ("CREATE TRIGGER `CirclesClosureSync` AFTER INSERT ON Circles
FOR EACH ROW BEGIN
    INSERT INTO CirclesClosure (ancestor, descendant) 
    SELECT ancestor, NEW.ID from CirclesClosure WHERE descendant=NEW.Parent;
    INSERT INTO CirclesClosure (ancestor, descendant) values (NEW.ID, NEW.ID);
END;");

$st->closeCursor();
?>

Hope this helps someone