Disclosed is a means and a method for executing a nested transaction in an execution environment supporting flat transactions only. To process a StartTransaction operation within a nested transaction it is suggested to check whether the StartTransaction operation is on the first nesting level of the nested transactions. An actual transaction within the execution environment by issuing a corresponding StartTransaction is started only in the affirmative case but not otherwise. To process a CommitTransaction operation within a nested transaction to successfully terminate a transaction it is suggested to check whether the CommitTransaction operation is on the first nesting level of the nested transaction. An actual transaction within the execution environment will be terminated only by issuing a corresponding CommitTransaction operation in the affirmative case but not otherwise. To process a RollbackTransaction operation within a nested transaction aborting a transaction as unsuccessful, it is suggested to issue a corresponding RollbackTransaction operation within the execution environment independent from the nesting level of said RollbackTransaction operation.