How to insert multiple rows in a mysql database at once with prepared statements?

This is completely valid:

$stmt = $mysqli->prepare("INSERT INTO something (userid, time, title) VALUES (?, ?, ?)");

$stmt->bind_param('iis', $userid, time(), $title);
$stmt->execute();

$stmt->bind_param('iis', $userid, time(), $title);
$stmt->execute();

$stmt->bind_param('iis', $userid, time(), $title);
$stmt->execute();

$stmt->bind_param('iis', $userid, time(), $title);
$stmt->execute();

You can foreach over your array of values to insert and bind and execute each time. It wont be quite as fast as the bulk insert in the example you linked, but it will be more secure.

You can build prepared statement using code as mentioned here,

PDO Prepared Inserts multiple rows in single query

PHP logic will be sort of like,

/**
 * Insert With Ignore duplicates in Mysql DB.
 */
public static function insertWithIgnore($em, $container, $tableName, $fields, $rows)
{
    $query = "INSERT IGNORE INTO $tableName (`" . implode('`,`', $fields) . "`) VALUES ";
    $placeHolr = array_fill(0, count($fields), "?");
    $qPart = array_fill(0, count($rows), "(" . implode(',', $placeHolr) . ")");
    $query .= implode(",", $qPart);

    $pdo = self::getPDOFromEm($em, $container);
    $stmt = $pdo->prepare($query);
    $i = 1;
    foreach ($rows as $row) {
        $row['created_at'] = date("Y-m-d H:i:s");
        foreach ($fields as $f) {
            if (!isset($row[$f])) {
                $row[$f] = null;
            }
            $stmt->bindValue($i++, $row[$f]);
        }
    }

    $result = $stmt->execute();

    if ($result == false) {
        $str = print_r($stmt->errorInfo(), true);
        throw new \Exception($str);
    }

    $stmt->closeCursor();
    $pdo = null;
}

/**
 * Replace old rows in Mysql DB.
 */
public static function replace($em, $container, $tableName, $fields, $rows, $extraFieldValues = null)
{
    if ($extraFieldValues != null) {
        $fields = array_unique(array_merge($fields, array_keys($extraFieldValues)));
    }

    $query = "REPLACE INTO $tableName (`" . implode('`,`', $fields) . "`) VALUES ";
    $placeHolr = array_fill(0, count($fields), "?");
    $qPart = array_fill(0, count($rows), "(" . implode(',', $placeHolr) . ")");
    $query .= implode(",", $qPart);

    $pdo = self::getPDOFromEm($em, $container);
    $stmt = $pdo->prepare($query);
    $i = 1;
    foreach ($rows as $row) {            
        if ($extraFieldValues != null) {
            $row = array_merge($row, $extraFieldValues);
        }
        foreach ($fields as $f) {
            $stmt->bindValue($i++, $row[$f]);
        }                        
    }
    $stmt->execute();
    if (!$stmt) {
        throw new \Exception("PDO::errorInfo():" . print_r($stmt->errorInfo(), true));
    }
    $stmt->closeCursor();
    $pdo = null;
}