my-first-goto.php

<?php

function createFoo()
{
    $pdo = new PDO(/*...*/);
    $maxTryCount = 3;
    $tryCount = 0;

    create_foo_start:
    try {
        $key = createMyOwnUniqueKey(); // e.g. foo-ear62-re4it
        $stmt = $pdo->prepare('INSERT INTO foo (key) VALUES (:key)');
        $stmt->execute(array(':key' => $key));
        return new Foo(/*...*/);
    } catch (PDOException $e) {
        if (preg_match('Duplicate entry.*for key \'key\'', $e->getMessage())) {
            if ($tryCount++ < $maxTryCount) {
                goto create_foo_start;
            }

            throw MyKeyIsNotReallyUniqueException('oh ein eichhörnchen. ich muss weg ...');
        }

        throw new FooCreationException;
    }
}