多项选择题
A.The tablespace has two data files.
B.An error is reported and tablespace creation fails.
C.Data files are created with names generated by the instance.
D.The tablespace can be extended without specifying the data file.
E.Data files belonging to the USERS tablespace cannot be renamed.
单项选择题 Your database is in NOARCHIVELOG mode and a logswitch happens every 20 minutes. On Thursday morning，media failure resulted in corruption of a data file belonging to the TOOLS tablespace. Backups are taken on every Sunday. What would you do in this situation？（）
单项选择题 Your database is running under automatic undo management and the UNDO_RETENTION parameter is set to 900 sec. You executed the following command to enable retention guarantee： SQL> ALTER TABLESPACE undotbs1 RETENTION GUARANTEE； What effect would this statement have on the database？（）
单项选择题 WhichstatementistruewhenyouruntheSQLTuningAdvisorwithlimitedscope？（）