Which two statements are true about alerts（） Clearing an alert sends the alert to the alert history.。 Response actions cannot be specified with server-generated alerts.。 The nonthreshold alerts appear in the DBA_OUTSTANDING_ALERTS view.。 Server-generated alerts notify the problems that cannot be resolved automatically and requireadministrators to be notified.。
国有企业事业单位职工参加基本养老保险前，视同缴费年限期间应当缴纳的基本养老保险费用由用人单位承担。
You started a long transaction. Before committing， you executed a query on one of the tables currently being modified. You received the following error： ORA-01555： snapshot too old How would you prevent such an error in the future？（） guarantee undo retention。 add one more redo log group。 size the redo log files appropriately。 size the UNDO tablespace appropriately。 size the SYSTEM tablespace appropriately。 configure an appropriate undo retention interval。 change automatic undo management to manual。
游戏性体验
You are connected using SQL* Plus to a multitenant container database (CDB) with SYSDBA privilegesand execute the following sequence statements:What is the result of the last SET CONTAINER statement and why is it so?（） It succeeds because the PDB_ADMIN user has the required privileges.。 It fails because common users are unable to use the SET CONTAINER statement.。 It fails because local users are unable to use the SET CONTAINER statement.。 If fails because the SET CONTAINER statement cannot be used with PDB$SEED as the target pluggable database (PDB).。
重大事故，是指造成（）
