Discern between SELECT, INSERT & UPDATE

gistfile1.php

$stmt = $this->connection->prepare($queryString);
$executeResult = !is_null($params)
    ? $stmt->execute($params)
    : $stmt->execute();
$data = $stmt->fetchAll($fetchType);

$isInsertStatement = empty($data)
    && $executeResult
    && ($lastInsertId = $this->connection->lastInsertId()) !== 0;
$isUpdateStatement = empty($data);

if ($isInsertStatement) {
    $data = array('insert_id' => $lastInsertId);
} else if ($isUpdateStatement) {
    $data = $executeResult;
}