The PL/SQL Challenge website has been down for most of the day, as we recover the database from 02:00 UTC 4 July. Our apologies for the inconvenience and lost opportunity to compete.
The results for 4 July will not be used in rankings and determining qualification in the Q3 championship playoff.
So if you are an American, it's just our way of saying: "Don't work (or 'play' with your technology)! Get away from your computer and celebrate the founding of your nation!"
Sigh.....
The PL/SQL Challenge (www.plsqlchallenge.com) offers a daily quiz on the PL/SQL language, through which thousands of Oracle technologists demonstrate and deepen their knowledge of PL/SQL. This blog contains posts by the PL/SQL Challenge founder, Steven Feuerstein, as well as comments from players.
04 July 2012
02 July 2012
Time for the Q2 2012 Championship Playoff!
The second quarter of 2012 ended last week...and that means it's time for the next championship playoff.
As you may recall, last quarter we initiated a new qualifier process in which selected players are asked to verify their performance during the quarter before being able to participate in the playoff.
I am very pleased to announce that none of the players this quarter will be required to take qualifier quizzes. What this means, in essence, is that none of the players submitted answers in astonishing and perhaps bewildering shorts amounts of time.
There is one other unusual aspect to the player group for this playoff: no players were able to qualify under the Wildcard category (see the FAQ for more information on how players are chosen).
In the table below, the number in parentheses after their names are the number of playoffs in which they have already participated. Congratulations to all listed on their accomplishment and best of luck in the upcoming competition!
We currently plan to hold the playoff on 26 July; that date may change if enough players are unable to play on that day.
As you may recall, last quarter we initiated a new qualifier process in which selected players are asked to verify their performance during the quarter before being able to participate in the playoff.
I am very pleased to announce that none of the players this quarter will be required to take qualifier quizzes. What this means, in essence, is that none of the players submitted answers in astonishing and perhaps bewildering shorts amounts of time.
There is one other unusual aspect to the player group for this playoff: no players were able to qualify under the Wildcard category (see the FAQ for more information on how players are chosen).
In the table below, the number in parentheses after their names are the number of playoffs in which they have already participated. Congratulations to all listed on their accomplishment and best of luck in the upcoming competition!
We currently plan to hold the playoff on 26 July; that date may change if enough players are unable to play on that day.
| Name | Rank | Qualification | Country |
|---|---|---|---|
| Frank Schrader (7) | 1 | Top 25 | Germany |
| Stelios Vlasopoulos (3) | 2 | Top 25 | Belgium |
| mentzel.iudith (6) | 3 | Top 25 | Israel |
| Viacheslav Stepanov (5) | 4 | Top 25 | Russia |
| Justin Cave (5) | 5 | Top 25 | United States |
| Rakesh Dadhich (0) | 6 | Top 25 | India |
| Jerry Bull (4) | 7 | Top 25 | United States |
| kowido (5) | 8 | Top 25 | No Country Set |
| Siim Kask (6) | 9 | Top 25 | Estonia |
| Vincent Malgrat (2) | 10 | Top 25 | French Republic |
| Sebastian Kolski (1) | 11 | Top 25 | Poland |
| Anna Onishchuk (5) | 12 | Top 25 | Ireland |
| _tiki_4_ (2) | 13 | Top 25 | Germany |
| Ivan Blanarik (1) | 14 | Top 25 | Slovakia |
| Niels Hecker (7) | 15 | Top 25 | Germany |
| Chad Lee (4) | 16 | Top 25 | United States |
| james su (4) | 17 | Top 25 | Canada |
| Dieter Kowalski (1) | 18 | Top 25 | Germany |
| swart260 (0) | 19 | Top 25 | Netherlands |
| Scott Wesley (1) | 20 | Top 25 | Australia |
| Sean Stuber (4) | 21 | Top 25 | United States |
| Randy Gettman (6) | 22 | Top 25 | United States |
| Giedrius Deveikis (0) | 23 | Top 25 | Lithuania |
| Zoltan Fulop (1) | 24 | Top 25 | Hungary |
| Mike Pargeter (6) | 25 | Top 25 | United Kingdom |
| Kevan Gelling (5) | 26 | Correctness | Isle of Man |
| Thierry Poels (3) | 63 | Correctness | Belgium |
| Syed Ariful Bari (3) | 84 | Correctness | Bangladesh |
| Yuan Tschang (3) | 86 | Correctness | United States |
| Vinu (0) | 90 | Correctness | India |
| Goran Stefanović (1) | 100 | Correctness | Serbia |
| anil_jha (0) | 105 | Correctness | United States |
| Frank Schmitt (1) | 114 | Correctness | Germany |
| John Rowbottom (1) | 200 | Correctness | United Kingdom |
| Kuzmin Konstanin (0) | 224 | Correctness | No Country Set |
30 June 2012
PL/SQL Challenge at Kscope12
I returned a few days ago from ODTUG's annual Kscope (formerly Kaleidoscope) conference, this year in hot, hot San Antonio, but located at the very comfortable and luxurious JW Marriott resort.
At the suggestion of Mike Brunstedt, one of our fabulous PL/SQL quiz reviewers, I made up a PL/SQL Challenger ribbon so that players and friends of the site could proudly proclaim their Challenger-ness:
We will also be giving them out at Oracle Open World in the Fall, so there's another reason to attend Larry's outsized celebration of all things Oracle.
It was great to meet players of the PL/SQL Challenge, and hear about how playing the quizzes has helped them in their work. It was even more of a pleasure to meet up with some of the reviewers who ensure the high quality of quizzes we play on the site:
At the suggestion of Mike Brunstedt, one of our fabulous PL/SQL quiz reviewers, I made up a PL/SQL Challenger ribbon so that players and friends of the site could proudly proclaim their Challenger-ness:
We will also be giving them out at Oracle Open World in the Fall, so there's another reason to attend Larry's outsized celebration of all things Oracle.
It was great to meet players of the PL/SQL Challenge, and hear about how playing the quizzes has helped them in their work. It was even more of a pleasure to meet up with some of the reviewers who ensure the high quality of quizzes we play on the site:
From left to right: Michael Brunstedt, Patrick Barel, Steven Feuerstein, Kim Berg Hansen
The PL/SQL Challenge wouldn't exist at all without the initial support and ongoing efforts by my Application Express expert friends at Apex Evangelists, so I demanded that they also join me for a photo:
From left to right: Dimitri Gielis, John Scott, Steven Feuerstein, Paul Broughton
Kscope12 was the usual fantastic conference, organized oh-so-well by Kathleen McCasland and her posse of capable women from Your Conference Connection, led by a friendly, enthusiastic board of directors.
Hope to see you there next year!
22 June 2012
PL/SQL Bug Confirmed from 20 June Quiz
The 20th June quiz tested your knowledge of how to remove "gaps" from a sparse array (make it dense). Daniel Kennedy posted an objection to the scoring, saying that if you use a NULL value for the index value in the collection, then none of the choices are correct.
This was a big surprise to many of us, who have long seen in our code that the idex value in an integer-indexed array cannot be NULL. Well....after checking with Bryn Llewellyn, Oracle PL/SQL Product Manager, I confirmed that this was a bug - and one that had not yet been reported!
So Bryn filed a bug report (1422744) with the explanation and code shown below.
Many aspects of the PL/SQL Challenge make me proud (the large number of players, their dedication, the growing body of knowledge about PL/SQL accessible in formats never available before, and so on). But when we identify bugs in the language or fixes required in the documentation, then I feel even more strongly how much the PL/SQL language can benefit from an active, engaged community.
Thanks, Daniel, for identifying this bug and for playing the PL/SQL Challenge.
Steven Feuerstein
v(null) := 42 succeeds when v is an IBBI – and brings Heisenberg exception handling
(from Bryn Llewellyn)
The testcase is copied below. Run it as any user with at least Create Session and Create Procedure.
The behavior of the varray and nested table tests is exactly as expected. Without the exception handling code, ORA-06502 is reported with a ORA-06512 for Line 9. And with the exception handling code, ORA-06502 is caught and nicely reported, and the program completes with no unhandled error.
However, IBBI_Test_1 runs without error and prints out 42. This is clearly a bug. Null is not a value. Rather, it's an indicator that expresses that the value is unknown.
Now it gets worse. IBBI_Test_2 simply adds the identical exception handler code for ORA-06502 around [v(null) := 42;] that Varray_Test_2 and Nested_Table_Test_2 use. But at run-time, we get this:
And finally, it gets worse still. IBBI_Test_3 adds more exception handling code. This time around [a := v(null);]. At run time, ORA-06502 is now obligingly caught at both [ v(null) := 42; ] and [ a := v(null); ].
This was a big surprise to many of us, who have long seen in our code that the idex value in an integer-indexed array cannot be NULL. Well....after checking with Bryn Llewellyn, Oracle PL/SQL Product Manager, I confirmed that this was a bug - and one that had not yet been reported!
So Bryn filed a bug report (1422744) with the explanation and code shown below.
Many aspects of the PL/SQL Challenge make me proud (the large number of players, their dedication, the growing body of knowledge about PL/SQL accessible in formats never available before, and so on). But when we identify bugs in the language or fixes required in the documentation, then I feel even more strongly how much the PL/SQL language can benefit from an active, engaged community.
Thanks, Daniel, for identifying this bug and for playing the PL/SQL Challenge.
Steven Feuerstein
v(null) := 42 succeeds when v is an IBBI – and brings Heisenberg exception handling
(from Bryn Llewellyn)
The testcase is copied below. Run it as any user with at least Create Session and Create Procedure.
The behavior of the varray and nested table tests is exactly as expected. Without the exception handling code, ORA-06502 is reported with a ORA-06512 for Line 9. And with the exception handling code, ORA-06502 is caught and nicely reported, and the program completes with no unhandled error.
However, IBBI_Test_1 runs without error and prints out 42. This is clearly a bug. Null is not a value. Rather, it's an indicator that expresses that the value is unknown.
Now it gets worse. IBBI_Test_2 simply adds the identical exception handler code for ORA-06502 around [v(null) := 42;] that Varray_Test_2 and Nested_Table_Test_2 use. But at run-time, we get this:
ERROR at line 1: ORA-06502: PL/SQL: numeric or value error: NULL index table key value ORA-06512: at "USR.IBBI_TEST_2", line 13 ORA-06512: at line 1
And finally, it gets worse still. IBBI_Test_3 adds more exception handling code. This time around [a := v(null);]. At run time, ORA-06502 is now obligingly caught at both [ v(null) := 42; ] and [ a := v(null); ].
------ Testcase ------
alter session set Plsql_Warnings = 'Enable:All'
/
create procedure Varray_Test_1 authid Definer is
type t is varray(10) of pls_integer;
v t;
a pls_integer;
n pls_integer;
-- PL/SQL: numeric or value error: NULL index table key value
ORA_06502 exception; pragma Exception_Init(ORA_06502, -06502);
begin
v(null) := 42; -- Line 9
end Varray_Test_1;
/
begin Varray_Test_1(); end;
/
create procedure Varray_Test_2 authid Definer is
type t is table of pls_integer;
v t;
a pls_integer;
n pls_integer;
-- PL/SQL: numeric or value error: NULL index table key value
ORA_06502 exception; pragma Exception_Init(ORA_06502, -06502);
begin
begin
v(null) := 42;
exception when ORA_06502 then
DBMS_Output.Put_Line('ORA-06502 on "v(null) := 42"');
end;
end Varray_Test_2;
/
begin Varray_Test_2(); end;
/
create procedure Nested_Table_Test_1 authid Definer is
type t is table of pls_integer;
v t;
a pls_integer;
n pls_integer;
-- PL/SQL: numeric or value error: NULL index table key value
ORA_06502 exception; pragma Exception_Init(ORA_06502, -06502);
begin
v(null) := 42; -- Line 9
end Nested_Table_Test_1;
/
begin Nested_Table_Test_1(); end;
/
create procedure Nested_Table_Test_2 authid Definer is
type t is table of pls_integer;
v t;
a pls_integer;
n pls_integer;
-- PL/SQL: numeric or value error: NULL index table key value
ORA_06502 exception; pragma Exception_Init(ORA_06502, -06502);
begin
begin
v(null) := 42;
exception when ORA_06502 then
DBMS_Output.Put_Line('ORA-06502 on "v(null) := 42"');
end;
end Nested_Table_Test_2;
/
begin Nested_Table_Test_2(); end;
/
create procedure IBBI_Test_1 authid Definer is
type t is table of pls_integer index by pls_integer;
v t;
a pls_integer;
n pls_integer;
begin
v(null) := 42;
a := v(null);
DBMS_Output.Put_Line(a);
end IBBI_Test_1;
/
begin IBBI_Test_1(); end;
/
create procedure IBBI_Test_2 authid Definer is
type t is table of pls_integer index by pls_integer;
v t;
a pls_integer;
n pls_integer;
-- PL/SQL: numeric or value error: NULL index table key value
ORA_06502 exception; pragma Exception_Init(ORA_06502, -06502);
begin
begin
v(null) := 42;
exception when ORA_06502 then
DBMS_Output.Put_Line(q'{ORA_06502 on "v(null) := 42"}');
end; -- Line 13
a := v(null);
DBMS_Output.Put_Line(a);
end IBBI_Test_2;
/
begin IBBI_Test_2(); end;
/
create procedure IBBI_Test_3 authid Definer is
type t is table of pls_integer index by pls_integer;
v t;
a pls_integer;
n pls_integer;
-- PL/SQL: numeric or value error: NULL index table key value
ORA_06502 exception; pragma Exception_Init(ORA_06502, -06502);
begin
begin
v(null) := 42;
exception when ORA_06502 then
DBMS_Output.Put_Line(q'{ORA_06502 on "v(null) := 42"}');
end;
begin
a := v(null);
exception when ORA_06502 then
DBMS_Output.Put_Line(q'{ORA_06502 on "a := v(null)"}');
end;
DBMS_Output.Put_Line(a);
end IBBI_Test_3;
/
begin IBBI_Test_3(); end;
/
19 June 2012
Big Mistake by Steven, No Quiz on Monday (for Many)
Dear PL/SQL Challenge Players,
I made a very big mistake today, and the result is that many of you could not play Monday's quiz.
I switched to maintenance mode at 15:00 to fix a bug, but then neglected to return to normal mode of play.
Then, seeing as I am in Taos, NM, I left the world of computers behind for Bandelier National Monument, an amazing place....but as a result, I did not notice that so many of you were notifying me of a problem with the site.
My deepest apologies. We will have to void the results for Monday's quiz.
I will change the site so that maintenance mode is always turned off after a period of time, so that if I happen to forget again, the site will correct itself.
Steven Feuerstein
I made a very big mistake today, and the result is that many of you could not play Monday's quiz.
I switched to maintenance mode at 15:00 to fix a bug, but then neglected to return to normal mode of play.
Then, seeing as I am in Taos, NM, I left the world of computers behind for Bandelier National Monument, an amazing place....but as a result, I did not notice that so many of you were notifying me of a problem with the site.
My deepest apologies. We will have to void the results for Monday's quiz.
I will change the site so that maintenance mode is always turned off after a period of time, so that if I happen to forget again, the site will correct itself.
Steven Feuerstein
15 June 2012
Gee Thanks, Amazon
Sure, Amazon Web Services are generally amazing and wonderful.
Except when they are not.
As you can read here, "parts of Amazon Web Services (AWS) suffered an outage on Thursday which led to a spread of high-profile sites clocking off the Web for the evening." Like the PL/SQL Challenge.
And 10 hours later, the PL/SAL Challenge site is still not available.
As a result, today's quiz will not be included in rankings for the quarterly championship.
My apologies to all players....
Steven Feuerstein
Except when they are not.
As you can read here, "parts of Amazon Web Services (AWS) suffered an outage on Thursday which led to a spread of high-profile sites clocking off the Web for the evening." Like the PL/SQL Challenge.
And 10 hours later, the PL/SAL Challenge site is still not available.
As a result, today's quiz will not be included in rankings for the quarterly championship.
My apologies to all players....
Steven Feuerstein
04 June 2012
Over 500,000 Answers Submitted on the PL/SQL Challenge!
Over the weekend of 2 June, we reached a major milestone on the PL/SQL Challenge: the 500,000th answer to a quiz was submitted!
Altogether, a total of 9,503 players from 120 countries have submitted (at the time of writing this post) 501,623 answers to quizzes. They used a total of 5770 days' time to decide on their choices and submit the answers.
Of course, the vast majority of those answers were submitted by a much smaller "core group" of Oracle technologists who play the daily PL/SQL quiz each day, or close to it.
Which means it's time for the Dedicated Players Roll Call. You will find below the list of all players who have missed no more than 50 daily PL/SQL quizzes out of the 559 that have been played since 8 April 2010. Now, that's dedication!
Dedicated Players Roll Call
Altogether, a total of 9,503 players from 120 countries have submitted (at the time of writing this post) 501,623 answers to quizzes. They used a total of 5770 days' time to decide on their choices and submit the answers.
Of course, the vast majority of those answers were submitted by a much smaller "core group" of Oracle technologists who play the daily PL/SQL quiz each day, or close to it.
Which means it's time for the Dedicated Players Roll Call. You will find below the list of all players who have missed no more than 50 daily PL/SQL quizzes out of the 559 that have been played since 8 April 2010. Now, that's dedication!
Dedicated Players Roll Call
| PLAYER | TAKEN | MISSED |
|---|---|---|
| Martin_Scholz_Berlin_Berlin |
558
|
1
|
| Patrick Barel |
558
|
1
|
| poelger |
555
|
4
|
| John Hall |
553
|
6
|
| Rohan Gray |
552
|
7
|
| DaveStadt-wbt |
550
|
9
|
| Ralf Koelling |
549
|
10
|
| Niels Hecker |
548
|
11
|
| Sterol Andro |
547
|
12
|
| Sean Molloy |
547
|
12
|
| Mike Pargeter |
543
|
16
|
| Anatoliy Kanivets |
542
|
17
|
| Zoltán Pásztor |
541
|
18
|
| João Barreto |
540
|
19
|
| Cliff Nadler |
540
|
19
|
| Scott Wesley |
539
|
20
|
| Frank Schrader |
538
|
21
|
| Jeroen Rutte |
537
|
22
|
| emha |
535
|
24
|
| VictorD |
533
|
26
|
| Marc Thompson |
533
|
26
|
| Otto Palenicek |
533
|
26
|
| Martin Mierke |
531
|
28
|
| Jim Schmitz |
531
|
28
|
| Alexander Koblov |
530
|
29
|
| Kevin Bentley |
530
|
29
|
| Rich Dellheim |
529
|
30
|
| Ronald Sönksen |
529
|
30
|
| Justin Cave |
529
|
30
|
| Henry Abeska |
528
|
31
|
| Janis Baiza |
528
|
31
|
| EdgarsP |
527
|
32
|
| Natarajan-wbt |
522
|
37
|
| Wolfgang Habermann |
521
|
38
|
| Michal Cvan |
521
|
38
|
| Markus Zuser |
521
|
38
|
| Marcus Matzberger |
520
|
39
|
| Hellmaster |
520
|
39
|
| Ivan Blanarik |
519
|
40
|
| Thierry Poels |
519
|
40
|
| CLW-wbt |
517
|
42
|
| Chad Lee |
516
|
43
|
| Naresh Kumar |
515
|
44
|
| Jeff Kemp |
514
|
45
|
| David Codl |
514
|
45
|
| William (Yi) Zhu |
512
|
47
|
| Bartek Goldman |
511
|
48
|
| Jens Petersen |
511
|
48
|
| Oliver Dimalanta |
511
|
48
|
| Jeyhun Gasimov |
510
|
49
|
| GabrieleR |
510
|
49
|
| Rob van den Berg |
510
|
49
|
| Radoslav Golian |
510
|
49
|
| Xavier Descamps |
510
|
49
|
| Geert Guldentops |
510
|
49
|
| Wim de Lange |
509
|
50
|
| Milan Vontorcik |
509
|
50
|
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