Re: write a sql block which will commit if both updates are successful else it will have to be rolled back

As documented under DO if you make an explicit transaction then execute the DO it cannot have transaction control commands.  If you allow it to “auto-commit’’ then it can.  Though in that case writing either rollback or commit for such a simple linear procedure becomes pointless since a transaction will already commit or rollback appropriately depending on whether the procedure provokes an exception.

David J.