like ""?

#11

onedbguru <onedbguru (AT) yahoo (DOT) com> wrote:

Quote:

All that I was saying was that you need to be careful... Not all
database engines treat empty string the same as null.

I don't know any such engine. But of course this would be a major flaw.

Quote:

In MySQL, it would be interesting to dump the data block to see what
is actually stored on disk to differentiate ES vs NULL.

NULL is not a value but rather a separate quality of a column. Most
engines in MySQL have a NULL bitmap associated with the row. If a
column is declared nullable, it has a bit in there and if the column
is NULL, then the bit is set and no value is stored for the column
at all. Details can be found in the "Internals Manual". i.e.

http://forge.mysql.com/wiki/MySQL_In...cord_Structure

XL

#12

El 03/03/2011 10:34, Axel Schwenke escribió/wrote:

Quote:

onedbguru<onedbguru (AT) yahoo (DOT) com> wrote:

All that I was saying was that you need to be careful... Not all
database engines treat empty string the same as null.

I don't know any such engine. But of course this would be a major flaw.

That engine is called Oracle.

--
-- http://alvaro.es - Álvaro G. Vicario - Burgos, Spain
-- Mi sitio sobre programación web: http://borrame.com
-- Mi web de humor satinado: http://www.demogracia.com
--

#13

On 2011-03-03 10:34, Axel Schwenke wrote:

Quote:

onedbguru <onedbguru (AT) yahoo (DOT) com> wrote:

All that I was saying was that you need to be careful... Not all
database engines treat empty string the same as null.

I don't know any such engine. But of course this would be a major flaw.

You don't have to look that far :-) Not sure if the situation still
exists, but it has been this way for long time. Found this link:

http://www.techonthenet.com/oracle/q...empty_null.php

/Lennart

[...]

#14

Lennart Jonsson wrote:

Quote:

On 2011-03-03 10:34, Axel Schwenke wrote:
onedbguru <onedbguru (AT) yahoo (DOT) com> wrote:
All that I was saying was that you need to be careful... Not all
database engines treat empty string the same as null.
I don't know any such engine. But of course this would be a major flaw.

You don't have to look that far :-) Not sure if the situation still
exists, but it has been this way for long time. Found this link:

http://www.techonthenet.com/oracle/q...empty_null.php

/Lennart

[...]

Yech. This really needs a definition the the SQL language itself to make
it one way or another, or code portability is badly affected..

#15

On 3/3/2011 6:56 AM, Lennart Jonsson wrote:

Quote:

On 2011-03-03 10:34, Axel Schwenke wrote:
onedbguru<onedbguru (AT) yahoo (DOT) com> wrote:

All that I was saying was that you need to be careful... Not all
database engines treat empty string the same as null.

I don't know any such engine. But of course this would be a major flaw.

You don't have to look that far :-) Not sure if the situation still
exists, but it has been this way for long time. Found this link:

http://www.techonthenet.com/oracle/q...empty_null.php

/Lennart

[...]

Hmmm, seems Oracle is seriously broken, according to the SQL91 standard.

I wonder if its still true in current versions of Oracle. I know both
DB2 and SQL Server have had it correct for a long time (DB2 way back in
the 80's).

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex (AT) attglobal (DOT) net
==================

#16

On 2011-03-03 22:21, Jerry Stuckle wrote:
[...]

Quote:

Hmmm, seems Oracle is seriously broken, according to the SQL91 standard.

I wonder if its still true in current versions of Oracle. I know both
DB2 and SQL Server have had it correct for a long time (DB2 way back in
the 80's).

Not sure, but I think it does (discussions about 11g regarding this
exists). I suspect it to be one of those backward compatibility things.

/Lennart

#17

On 2011-03-03 13:00, The Natural Philosopher wrote:
[...]

Quote:

Yech. This really needs a definition the the SQL language itself to make
it one way or another, or code portability is badly affected..

The definition do exists. I might be wrong but I think this is why
Oracle introduced the varchar2 data type. Perhaps someone with a greater
insight can fill in the details?

/Lennart

#18

In article <ikp0p0$ahv$1 (AT) news (DOT) eternal-september.org>, Jerry Stuckle <jstucklex (AT) attglobal (DOT) net> wrote:

Quote:

On 3/3/2011 6:56 AM, Lennart Jonsson wrote:
On 2011-03-03 10:34, Axel Schwenke wrote:
onedbguru<onedbguru (AT) yahoo (DOT) com> wrote:

All that I was saying was that you need to be careful... Not all
database engines treat empty string the same as null.

I don't know any such engine. But of course this would be a major flaw.

You don't have to look that far :-) Not sure if the situation still
exists, but it has been this way for long time. Found this link:

http://www.techonthenet.com/oracle/q...empty_null.php

/Lennart

[...]

Hmmm, seems Oracle is seriously broken, according to the SQL91 standard.

I wonder if its still true in current versions of Oracle.

Still true in 10g, which is the latest version I have experience with.

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