Disqus - Latest Comments for Laurent Schneider

Re: New commenting feature: Edit comments inline

Laurent Schneider — Fri, 11 Apr 2008 06:10:34 -0000

I have tried this a few times, and it seems buggy when used with code tags, part of the code disappear. I hope you will fix this :-)

Re: 11g Doc Makeover: Part 2

Laurent Schneider — Fri, 14 Sep 2007 15:20:53 -0000

I have written so many of comments in the doc (especially in sql) that I have been included as a contributor in one book! totally unexpected... My last comment, what is the difference between atan(x/y) and atan2(x,y) ;-)

Well, comments made on the productive doc cannot be corrected as fast as the beta doc, but still the author occasionally come back to me when they need more info. That's why I always post my email address when writing a comment 8-)

Re: Which Operating System Would You Have Your Child Use?

Laurent Schneider — Mon, 12 Jan 2009 07:47:13 -0000

I have two kids, 5 and 6, they are just fine starting their online games in any browser (linux/mac/win) , for instance http://www.tiji.fr

I am not sure a SUV and Vista is bad choice for your kids... well, maybe you are too much of a Linux advocate :)

Kids like games. I meant not THE game you chose for them, but the SAME game as your neighbours are playing... Kids also like cars, and when you go skiing with your family, it is best to have something larger than a Smart.

My kids ? They use Vista Premium at home, and I drive a 1.8l Sharan ;)

Re: A Different World

Laurent Schneider — Tue, 27 Sep 2005 17:32:55 -0000

:-)
people not living in the usa often appreciate the freedom to have a beer in the morning, to drink wine at lunch time, to smoke a havana cigare after dinner...

just a different world !

I have just asked during my last trip in SF why there were no wine at lunch time. I got the -imho- extremly funny answer : because the russians drink wodka at lunch and after they do not go to work in the afternoon!

cheers!
laurent

Re: A Different World

Laurent Schneider — Thu, 29 Sep 2005 06:03:08 -0000

In Switzerland, the bus will never turn on his motor before driving, it is not allowed to let the motor runs with noone is in the car. In one village called Zermatt (quite well known), only electrical engines are admitted!

If you have to stop on red light for a fairly long time (more than 2 minutes), you should turn off your engine.

Their is a joke about swiss people:
- it is 17:04. The 17:02 train has not arrived yet. What is the problem?
1) it is not a swiss train
2) it is not a swiss watch

Re: Cool SQL function: EXTRACT

Laurent Schneider — Wed, 28 Dec 2005 09:36:36 -0000

interesting is extracting nanoseconds from timestamp :

SQL> create table t as select timestamp '2000-01-01 00:00:42.123456789' t from dual;

Table created.

SQL> select mod(extract(second from t),1)*1000000000 ns from t;
NS

123456789

Re: NVL, NVL2 or COALESCE?

Laurent Schneider — Fri, 27 Jan 2006 10:20:07 -0000

(maybe more?)

select decode(x,0,null,x) from t;

select nullif(x,0) from t;

Re: Search Oracle Docs and read OraBlogs from Google toolbar

Laurent Schneider — Wed, 01 Feb 2006 10:40:14 -0000

too sad I do not have enough right to install gg tb on my pc here.

Well, on my notebook, i never use that kind of nonoperating system anyway.

Thanks for the link!

Re: Undocumented LNNVL SQL function now safe to use

Laurent Schneider — Tue, 26 Sep 2006 05:52:14 -0000

I would not even pretend it is safe to use in 10g !

SQL> select * from dual where not lnnvl(1=1);
select * from dual where not lnnvl(1=1)
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel

Re: World Population = World Population + 1

Laurent Schneider — Wed, 27 Sep 2006 07:24:09 -0000

congats !

Re: Give Me One Minute And I’ll Tell You If You Are Liberal Or Conservative

Laurent Schneider — Mon, 06 Nov 2006 05:31:14 -0000

What about using CROSS JOIN and FULL NATURAL JOIN ?

Re: Bart’s Punishment For Asking Dumb Questions

Laurent Schneider — Tue, 14 Nov 2006 12:44:03 -0000

I have seen read the fine manual too. Also funny is http://googleityoumoron.com

Once I almost wrote
RTFM twice
but I wrote :
tahiti.oracle.com

:-)

Re: Bart’s Punishment For Asking Dumb Questions

Laurent Schneider — Wed, 15 Nov 2006 15:57:31 -0000

http://download-uk.oracle.com/robots.txt
interesting to read that the robots are disallowed to access the beta documentation :-p

Re: links for 2006-12-08

Laurent Schneider — Fri, 08 Dec 2006 06:28:31 -0000

my 2 cents on NULL values in a database

I strongly disagree with the conclusion of the article. Even if I could understand that "unknown" gender is somewhat confusing and could lead to poor data quality, it is highly irrelevant to fill all optional columns of your data with 0 or space. I hate much more queries like where x = ' ', but because a developer hated nulls at that time.

Also deeply stupid are datamodels where the child table (cardinality 1:0,n) has ID=-1 for inexistant childs, which is completely misleading, for both dba and optimiser.

I do not have nulls. The one I do not like too much is length('') is null, but as written in doc 7,8,8i,9,10,11, it may change in a next release :evil:

Re: links for 2006-12-08

Laurent Schneider — Sat, 09 Dec 2006 03:29:56 -0000

this about nan, not null :evil:

http://preview.tinyurl.com/ybmkhh

Re: links for 2006-12-08

Laurent Schneider — Sat, 09 Dec 2006 03:31:09 -0000

[i]an excellent job of demonstrating what total innumerate idiots reporters are.[/i]

:twisted:

Re: Two Oracle PL/SQL Features You Probably Don’t Know About

Laurent Schneider — Mon, 30 Apr 2007 06:01:11 -0000

I had a good explanation of mutual recursion at school, a long time ago.

Simple recursion : you see yourself in a mirror, and in the mirror you see a small mirror where you see you again, and again.

Mutual recursion is : a boy is drawing a girl, the girl is drawing the boy (with a drawing of herself, drawing him, ...).

In Pascal, you had to add the keyword forward to do this.

Have a nice day,
Laurent

Re: Two Oracle PL/SQL Features You Probably Don’t Know About

Laurent Schneider — Sun, 13 May 2007 02:24:23 -0000

Do not you need a package to use mutual recursion?

Re: Two Oracle PL/SQL Features You Probably Don’t Know About

Laurent Schneider — Tue, 15 May 2007 11:14:18 -0000

LOL ! There you have encapsulated two functions in one... it is almost a package!

Seriously, you cannot have

create function f1 return number is begin return f2; end;
/

create function f2 return number is begin return f1; end;
/

Re: When ANSI SQL Join Syntax Does Not Work in Oracle

Laurent Schneider — Mon, 18 Jun 2007 11:54:47 -0000

what about this...

select u1.object_name, u1.object_type, u2.object_type, u2.object_type
from all_objects u1 full outer join all_objects u2 on
(u1.object_name=u2.object_name);

from all_objects u1 full outer join all_objects u2 on
*
ERROR at line 2:
ORA-00904: "XML_SCHEMA_NAME_PRESENT"."IS_SCHEMA_PRESENT": invalid identifier

Re: When ANSI SQL Join Syntax Does Not Work in Oracle

Laurent Schneider — Mon, 18 Jun 2007 11:57:51 -0000

well, to make sense the query condition should contain

and u1.owner='FOO' and u2.owner='BAR'

but the bug is the same... not found on metalink yet

Re: Guess How Many Database Editions Oracle Has

Laurent Schneider — Thu, 06 Dec 2007 04:09:19 -0000

The fifth edition is unfortunately not available on Linux. Personal Edition is the cheapest way for an independant consultant to get access to patches and to Metalink

Re: Cool Undocumented SQL Function SYS_OP_MAP_NONNULL and Some Alternatives

Laurent Schneider — Thu, 06 Dec 2007 11:26:57 -0000

I tried
<pre>
select * from dual where sys_op_map_nonnull(null) = 'FF' ;
D
-
X
</pre>
It does return a row on my 10.2.0.3

Re: Give Me The Current Date Please

Laurent Schneider — Fri, 18 Apr 2008 02:19:29 -0000

> then you have no daylight saving issues for instance
some issues are related to Oracle and to the goverments changing rules over and over. Did you a know an island with about 500 people and 1000 birds did introduce a half-an-hour summer offset that produced bugs in 10gR2 :)

select timestamp '2007-10-27 15:00:00 +00:00' at time zone 'Australia/LHI' from dual;
ORA-01878: specified field not found in datetime or interval

But yes, using date instead of timestamp is probably not the best approach. Still a lot of function do not work with timestamp, like LAST_DAY, ADD_MONTHS and TRUNC

Re: Cool Undocumented OVERLAPS Predicate

Laurent Schneider — Fri, 13 Jun 2008 01:49:12 -0000

WM_OVERLAPS is documented

SELECT *
FROM dual
WHERE WM_OVERLAPS(WM_PERIOD(add_months(sysdate, -6), DATE '2008-08-08'),
WM_PERIOD(sysdate - 180, sysdate+180))=1;

Re: SQL Function Spotlight: TRIM

Laurent Schneider — Fri, 29 Aug 2008 01:35:50 -0000

there is one major advantage of using ltrim (rtrim), with ltrim you can skip any character from a range, with trim the character is a single character !
<pre>
SQL> select ltrim('elcaroracle','racle') from dual

LTRIM(
------
oracle
</pre>