单项选择题
A.It records usernames and passwords of users when granted the DBA role.
B.It contains usernames and passwords of users for whom auditing is enabled.
C.It is used by Oracle to authenticate users for remote database administration.
D.It records usernames and passwords of all users when they are added to OSDBA or OSOPER operatingsystem groups
单项选择题 You used the IMMEDIATE option to shut down your database instance. Consider the steps that may occurwhen a database instance is started and database is opened： 1. SGA is allocated. 2. Control file is read. 3. Redo log files are opened.4. Instance recovery is started. 5. Background processes are started. 6. Data file headers are checked for consistency. 7. Server parameter file or the initialization parameter file is read. Which option has the correct order in which these steps occur（）
单项选择题 Your database instance is configured with automatic undo management and the UNDO_RETENTIONparameter is set to 900 seconds. You executed the following command to enable retention guarantee: SQL> ALTER TABLESPACE undotbs1 RETENTION GUARANTEE; What effect would this command have onthe database（）
单项选择题 Youwanttoenablearchivingonyourdatabase.Presently，thedatabaseisrunninginNOARCHIVELOGmode.Givenbelowarethestepstoaccomplishthetaskinrandomorder： 1.Shutdowntheinstance. 2.ExecutetheALTERDATABASEARCHIVELOGcommand. 3.Startuptheinstanceandmountthedatabase. 4.SettheDB_RECOVERY_FILE_DESTinitializationparameterto$ORACLE_HOME/dest_1. 5.Openthedatabase. Whichisthecorrectsequenceofstepsforaccomplishingthetask（）