public function lockRead($alias = null)
{
if (!$alias) {
$alias = $this->alias;
}
// the ::table consts is in the child class.
if ($alias) {
$sql = 'LOCK TABLES ' . $this->table . ' AS ' . $alias . ' READ';
} else {
$sql = 'LOCK TABLES ' . $this->table . ' READ';
}
$this->getReadConnection()->query($sql);
}