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Only select on External Tables

原创 Linux操作系统 作者:yyp2009 时间:2012-03-14 16:46:54 0 删除 编辑

QUESTION

EMPDET is an external table containing the columns EMPNO and ENAME. Which command
would work in relation to the EMPDET table?
A. UPDATE empdet
SET ename = 'Amit'
WHERE empno = 1234;
B. DELETE FROM empdet
WHERE ename LIKE 'J%';
C. CREATE VIEW empvu
AS
SELECT * FROM empdept;
D. CREATE INDEX empdet_idx
ON empdet(empno);

reference :
1 You can connect to the database and create metadata for the external table using DDL. The DDL for an external table consists of two parts: one part that describes the Oracle column types, and another part (the access parameters) that describes the mapping of the external data to the Oracle data columns.

2 External tables are read only; therefore, no DML operations are possible, and no index can be created on them.

3 nonsupport LOB

4 before load you can query

5 extensive transformations on load

6 pipellininn

7 load big table

8 non temp table

9 non  physical space

……

  Only os datafile!hehe

 

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