To allocate another role to a user, which command is most appropriate?（）

单项选择题Youareattemptingtoclearanunarchivedredologfile.Inordertomanuallyenactalogswitch,whichofthefollowingstatementsisappropriate?（）

A.ALTER DATABASE 
B.ALTER SYSTEM 
C.ALTER USER 
D.ALTER REDO LOG

单项选择题YouareanalyzingthecomponentsoftheredologmechanismsinyourOracledatabase.WhichofthefollowingpurposesdoestheCKPTprocessserve?（）

A.Writes buffers to disk 
B.Writes current redo log number to datafile headers 
C.Writes redo log information to disk 
D.Reads information into memory for users

单项选择题TheDBAisdefiningroleforusers.Whichofthefollowingisnotanacceptablemethodfordefiningadefaultrole?（）

A.ALTER USER DEFAULT ROLE ALL
B.ALTER USER DEFAULT ROLE ALL EXCEPT ROLE_1
C.ALTER USER DEFAULT ROLE NONE
D.ALTER USER DEFAULT ROLE NONE EXCEPT ROLE_1

单项选择题YouaredefiningareasonyourOracledatabase.Whichofthefollowingprofileareascanbeusedtocontroltheresourceusagefortheotherfour?（）

A.LOGICAL_READS_PER_SESSION 
B.CONNECT_TIME 
C.COMPOSITE_LIMIT 
D.CPU_PER_SESSION 
E.PRIVATE_SGA

单项选择题Inasituationwherenomultiplexingofredologstakesplace,whathappenswhenOraclecannotreaddatafromtheonlineredologgroupforarchiving?（）

A.Nothing happens
B.Oracle will automatically switch redo logs when detected 
C.Oracle eventually won't allow new records to be added to the database 
D.The instance crashes