多项选择题
Which two are true regarding external tables？ （）
A.External tables can be updated.
B.External tables are read-only tables.
C.Indexes can be created on external tables.
D.Indexes cannot be created on external tables.
相关考题
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单项选择题
Consider the following statement： SQL> EXECUTE DBMS_STATS.GATHER_SHEMA_STATS （- 2> ownname => ‘OE’， - 3> estimate_percent => DBMS_STATS.AUTO_SAMPLE_SIZE， - 4> method opt => ‘for all columns size AUTO’）； What is the effect of ‘for all columns size AUTO’ of the METHOD_OPT option？（）
A.The Oracle server creates a new histogram based on existing histogram definitions for all table, column, and index statistics for the OE schema.
B.The Oracle server creates a histogram based on data distribution regardless of how the application uses the column/s for all table, column, and index statistics for the OE schema.
C.The Oracle server creates a histogram based on data and application usage of the column/s for all table, column, and index statistics for the OE schema.
D.The Oracle server creates a histogram based on application usage, regardless of data distribution, for all table, column, and index statistics for the OE schema. -
多项选择题
Examine the list of variables and their data types： AME DATA Type TS， TS1 TIMESTAMP TSZ TIMESTAMP WITH TIME ZONE TLZ TIMESTAMP WITH LOCAL TIME ZONE IYM INTERVAL YEAR TO MONTH IDS， IDSI INTERVAL YEAR To SECOND Which three expressions using the new data and time data types are valid？（）
A.IDS* 2
B.TS + IYM
C.TS –TSI
D.IDS – TS
E.IDS + IYM -
单项选择题
Whatistrueifyouwanttoswitchundotablespacesfromthecurrentone，calledUNDO1，toanewonecalledUNDO2？（）
A.It is NOT possible to switch unless no active transaction exist in UNDO1.
B.It is possible to switch to UNDO2； but current active transactions will abort.
C.It is possible to switch to UNDO2； current active transactions will be automatically migrated to UNDO2.
D.It is possible to switch to UNDO2； only current active transactions will continue to execute inside UNDO1.
