/**
* Updates existing rows.
*
* @param array $data Column-value pairs.
* @param array|string $where An SQL WHERE clause, or an array of SQL WHERE clauses.
* @return int The number of rows updated.
*/
public static function update(array $data, $where)
{
$tableSpec = (static::$_schema ? static::$_schema . '.' : '') . static::$_name;
return static::$_db->update($tableSpec, $data, $where);
}