Rolls back all outstanding statements for the Oracle
connection.
Note: Transactions are automatically rolled back when you close the connection, or when the script ends, whichever is soonest. You need to explicitly call oci_commit() to commit the transaction, or oci_rollback() to abort it.
Note: In PHP versions before 5.0.0 you must use ocirollback() instead. This name still can be used, it was left as alias of oci_rollback() for downwards compatability. This, however, is deprecated and not recommended.