Test: Quiz: Modifying a Table

Test: Quiz: Modifying a Table

Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.

Section 1
(Answer all questions in this section)

1. Comments can be added to a table by using the COMMENT ON TABLE statement. The comments being added are enclosed in: Mark for Review
(1) Points


Double quotes " "


Single quotes ' ' (*)


Parentheses ( )


Brackets { }



Correct


2. To completely get rid of a table, its contents, its structure, AND release the storage space the keyword is: Mark for Review
(1) Points


DROP (*)


DELETE


TRUNCATE


KILL



Correct


3. When you use ALTER TABLE to add a column, the new column: Mark for Review
(1) Points


Becomes the first column in the table


Becomes the last column in the table (*)


Can be placed by adding a GROUP BY clause


Will not be created because you cannot add a column after the table is created



Correct


4. After issuing a SET UNUSED command on a column, another column with the same name can be added using an ALTER TABLE statement. True or False? Mark for Review
(1) Points


True (*)


False



Correct


5. The FLASHBACK TABLE to BEFORE DROP can restore only the table structure, but not its data back to before the table was dropped. True or False? Mark for Review
(1) Points


True


False (*)



Incorrect. Refer to Section 8 Lesson 3.


6. You can use the ALTER TABLE statement to: Mark for Review
(1) Points


Add a new column


Modify an existing column


Drop a column


All of the above (*)



Correct


7. A columnﾒs data type can always be changed from NUMBER to VARCHAR2 but not from VARCHAR2 to NUMBER, provided the table is empty. True or False? Mark for Review
(1) Points


True


False (*)



Correct


8. ALTER TABLE table_name RENAME can be used to: Mark for Review
(1) Points


Rename a row.


Rename a column.


Rename a table. (*)


All of the above.



Correct


9. Which of the following will correctly change the name of the LOCATIONS table to NEW_LOCATIONS? Mark for Review
(1) Points


ALTER TABLE LOCATIONS RENAME NEW_LOCATIONS


MODIFY TABLE LOCATIONS RENAME NEW_LOCATIONS


RENAME LOCATIONS TO NEW_LOCATIONS (*)


None of the above; you cannot rename a table, you can only CREATE, ALTER and DROP a table.



Correct


10. You can use DROP COLUMN to drop all columns in a table, leaving a table structure with no columns. True or False? Mark for Review
(1) Points


True


False (*)



Correct


11. The FLASHBACK QUERY statement can restore data back to a point in time before the last COMMIT? True or False? Mark for Review
(1) Points


True


False (*)



Correct


12. The following code creates a table named student_table with four columns: id, lname, fname, lunch_num;
CREATE TABLE student_table
(id NUMBER(6),
lname VARCHAR(20),
fname VARCHAR(20),
lunch_num NUMBER(4));

The lunch_num column in the above table has been marked as UNUSED. Which of the following is the best statement you can use if you wish to remove the UNUSED column from the student_table?

Mark for Review
(1) Points


DROP column


ALTER TABLE DELETE UNUSED COLUMNS


ALTER TABLE DROP UNUSED COLUMNS (*)


ALTER TABLE DELETE ALL COLUMNS



Correct


13. When should you use the SET UNUSED command? Mark for Review
(1) Points


Never, there is no SET UNUSED command


You should use it if you think the column may be needed again later


You should use it when the system is being heavily used (*)


You should only use this command if you want the column to still be visible when you DESCRIBE the table



Correct


14. The data type of a column can never be changed once it has been created. True or False? Mark for Review
(1) Points


True


False (*)



Correct