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发布时间:2019-10-21 11:39:52

Which three statements are true about dropping and unused columns in an Oracle database?B) A DROP COLUMN command can be rolled backD) An UNUSED column's space is redaimed automatially when the row containing that column is next queried.F) A column that is set to NNUSED still counts tow.........【阅读全文】

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发布时间:2019-10-21 10:25:04

Which two statements are true about a self join?B) It can be a left outer join.D) It can be an inner join.Answer:BD不过在进行内连接时为了区别表的名字,需要加别名from emp2 won w.mgr=m.empno;)......【阅读全文】

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发布时间:2019-10-18 14:51:08

Which two statements are true about Oracle synonyms?B) All private synonym names must be unique in the database.D) A synonym can be created on an object in a package.(解析:同义词也是 Oracle 的一个对象;......【阅读全文】

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发布时间:2019-10-18 09:36:29

Which three statements are true about views in an Orade batabase?B) Rows inserted into a table using a view are retained in the table if the view is doppedD) Views have no segment.F) A view can be created that refers to a non-existent table in its defining query.(解析:.........【阅读全文】

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发布时间:2019-10-17 11:49:07

The EMPLOYEES table contains columns EMP_ID of data type NUMBER and HIRE_DATE of data type DATEThe NLS_TERRITORY parameter is set to AMERICA in the session and, therefore, Sunday is the first day ofthe weekA) SELECT emp_id,NEXT_DAY(ADD_MONTHS(hite_date,6), 'MONDAY') FROM employees;C) S.........【阅读全文】

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