多项选择题
Which two statements are true about a bitmap index？ （）
A.It is recommended for the columns that have unique values.
B.It can be converted to a B-tree index by using the ALTER INDEX command.
C.It has a bitmap segment for each distinct value in the key column， containing a string of bits in which each bit represents the presence or absence of a key column value.
D.Updating the key column locks the whole bitmap segment that contains the bit for the key value to be updated.
相关考题
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单项选择题
Examine the following commands executed in your database： SQL> ALTER SESSION RECYCLEBIN=ON； Session altered SQL> CREATE TABLE emp TABLESPACE tbsfd AS SELECT * FROM hr.employees； Table created. Further， you executed the following command to drop the table： SQL> DROP TABLE emp； Table dropped. What happens in this scenario？ （）
A.The table is moved to the SYSAUX tablespace.
B.The table is moved to the SYSTEM tablespace.
C.The table is removed from the database permanently.
D.The table is renamed and remains in the TBSFD tablespace. -
单项选择题
You execute the following command to audit the database activities： SQL> AUDIT DROP ANY TABLE BY scott BY SESSION WHENEVER SUCCESSFUL； What is the effect of this command？（）
A.One audit record is created for the whole session if user SCOTT successfully drops one or more tables in his session.
B.One audit record is created for every session when any user successfully drops a table owned by SCOTT.
C.One audit record is created for each successful DROP TABLE command executed by any user to drop tables owned by SCOTT.
D.One audit record is generated for the session when SCOTT grants the DROP ANY TABLE privilege to other users in his session.
E.One audit record is created for each successful DROP TABLE command executed in the session of SCOTT. -
单项选择题
Youhavealargeamountofhistoricaldatainanoperatingsystemfile.Someanalystsinyourorganizationneedtoquerythisdata.Thefileistoolargetoloadintoyourcurrentdatabase.Whichisthemosteffectivemethodtoaccomplishthetask？（）
A.Upgrade the hardware/memory to accommodate the data.
B.Load the data into your database by using the PARALLEL clause.
C.Give analysts DBA privilege， so that they can query DBA_EXTERNAL_TABLES.
D.Use an external table so you can have the metadata available in your database， but leave the data in the operating system files.
