duminică, 2 mai 2010

Test: Quiz: Sequences

Review your answers, feedback, and question scores below. An asterisk (*) indicates a correct answer.
Section 1
1. A sequence is a database object. True or False? Mark for Review
(1) Points
True (*)
False
CorrectCorrect
2. NEXTVAL and CURRVAL are known as column aliases. True or False? Mark for Review
(1) Points
True
False (*)
CorrectCorrect
3. Which keyword is used to modify a sequence? Mark for Review
(1) Points
Change.
Update.
Alter. (*)
Create.
CorrectCorrect
4. When you alter a sequence, a new increased MAXVALUE can be entered without changing the existing number order. True or False? Mark for Review
(1) Points
True (*)
False
Correct Correct
5. Why do gaps in sequences occur? Mark for Review
(1) Points
A rollback is executed.
The system crashes.
The sequence is used in another table.
All of the above. (*)
Correct Correct
6. A sequence is a window through which data can be queried or changed. True or False? Mark for Review
(1) Points
True
False (*)
Correct Correct
7. CURRVAL is a pseudocolumn used to refer to a sequence number that the current user has just generated by referencing NEXTVAL. True or False? Mark for Review
(1) Points
True (*)
False
Correct Correct
8. Examine the code for creating this sequence:

CREATE SEQUENCE track_id_seq
INCREMENT BY 10
START WITH 1000 MAXVALUE 10000

What are the first three values that would be generated by the sequence?

Mark for Review
(1) Points
100010011002.
1000, 1010, 1020. (*)
1100, 1200, 1300.
0, 1, 2.
Correct Correct
9. In order to be able to generate primary key values that are not likely to contain gaps, which phrase should be included in the sequence creation statement? Mark for Review
(1) Points
NOCACHE. (*)
CACHE.
MAXVALUE.
Correct Correct
10. Which keyword is used to remove a sequence? Mark for Review
(1) Points
Drop. (*)
Delete.
Remove.
Revoke.
CorrectCorrect
11. CURRVAL is a pseudocolumn used to extract successive sequence numbers from a specified sequence. True or False? Mark for Review
(1) Points
True
False (*)
Correct Correct
12. Which is the correct syntax for specifying a maximum value in a sequence? Mark for Review
(1) Points
Maxval.
Max_value.
Maximumvalue.
Maxvalue. (*)
CorrectCorrect


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