Comments on: The UNKNOWN null. https://technology.amis.nl/2006/08/27/the-unknown-null/ Friends of Oracle and Java Sat, 25 Apr 2015 11:36:47 +0000 hourly 1 http://wordpress.org/?v=4.2 By: Patrick Sinke https://technology.amis.nl/2006/08/27/the-unknown-null/#comment-3785 Tue, 29 Aug 2006 08:22:24 +0000 http://technology.amis.nl/blog/?p=1320#comment-3785 And that’s a thing I did not know… I always thought that ” != null. About time they change that…..

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By: Laurent Schneider https://technology.amis.nl/2006/08/27/the-unknown-null/#comment-3784 Mon, 28 Aug 2006 16:04:54 +0000 http://technology.amis.nl/blog/?p=1320#comment-3784 One I do hate about nulls is this one

select length(”) from dual;
LENGTH
———
NULL

of course one would expect to have 0 as the length of an empty string.

Still Oracle may change this in a very future release, as stated in
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/sql_elements005.htm#sthref486

Oracle Database currently treats a character value with a length of zero as null. However, this may not continue to be true in future releases, and Oracle recommends that you do not treat empty strings the same as nulls.

it will be fun I promise !

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By: Viliam https://technology.amis.nl/2006/08/27/the-unknown-null/#comment-3783 Mon, 28 Aug 2006 15:32:36 +0000 http://technology.amis.nl/blog/?p=1320#comment-3783 It’s quite complicated even for some Oracle programmers, see this bug: http://forums.oracle.com/forums/thread.jspa?threadID=415338

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By: Chen Shapira https://technology.amis.nl/2006/08/27/the-unknown-null/#comment-3782 Mon, 28 Aug 2006 08:39:11 +0000 http://technology.amis.nl/blog/?p=1320#comment-3782 Thats a terriffic summary! No matter how long you’ve been looking at databases, NULLs always remain a bit unexpected. I’ve bookmarked this article and will probably refer to it time and again when things get murky again :-)

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