select to be a DRL (Data Retrieval Language) statement. rollback. This is possible because the necessary information is stored in undo data. for update clause and the lock table statement, lock the entire table with a table lock (aka TM lock). dbms_errlog and the log errors clause in insert statements. optimizer_real_time_statistics controls whether Oracle gathers real-time statistics during conventional DML. feedback to on in SQL*Plus reports the number of records affected after executing a DML statement.