Discards database commands that were issued after calling PDO::beginTransaction and returns the connection to auto commit mode.
bool PDO::rollBack ();
true if the method call succeeded, false otherwise.
PDO::rollback is not affected by (and does not affect) the value of PDO::ATTR_AUTOCOMMIT.
See PDO::beginTransaction for an example that uses PDO::rollback.
Support for PDO was added in version 2.0 of the Microsoft Drivers for PHP for SQL Server.