abortExternalTransaction() updating;
The abortExternalTransaction method of the ExternalDatabase class rolls back the changes made during the current transaction. If the external database supports transactions, use this method to undo the effects of a transaction, if required. All updating operations (creates, deletes, or updates) made since the last beginExternalTransaction call are reversed to the state that existed at the time of that call.
If the external database does not support transactions (use the canTransact method to determine this), calling the abortExternalTransaction method has no effect.