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);
Can any one explain this to me why update command will not work???
This is an external table, so I think you can update it directly.
No, you can not.
what is the meaning of external table
I can see nnow that I made a mistake in my previous update.
It should be: you cannot update external table. You also cannot insert any data.
Via external table you have access to data that are in flat file.
External table behaves like a common table in database when you want to select data.
You can select, join, or sort external table data. You can also create views and synonyms for external tables. However, no DML operations (UPDATE, INSERT, or DELETE) are possible, and no indexes can be created, on external tables.
c
I have the same idea. C