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From:emierzwa Date:December 11 2006 2:50pm
Subject:RE: UNIQUE KEY vs NULLs
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It is expected behavior, you can make the unique key a primary key
instead. This should prevent this situation.

Ed 

-----Original Message-----
From: imre@stripped [mailto:imre@stripped] 
Sent: Monday, December 11, 2006 7:42 AM
To: mysql@stripped
Subject: UNIQUE KEY vs NULLs

Hi,

I have an InnoDB table similar to this:

CREATE TABLE Target
(IMSI VARCHAR(15) ASCII,
 IMEI VARCHAR(15) ASCII,
 UNIQUE KEY (IMSI, IMEI));

After playing a bit with it, I managed to add duplicate records, if one
of
the fields was a NULL:

+-----------------+-----------------+
| IMSI            | IMEI            |
+-----------------+-----------------+
| NULL            | 35195600126418  |
| NULL            | 35195600126418  |
+-----------------+-----------------+


Is this a bug, or a feature? :-)

If it is a feature, than how can I assure uniqueness for a table in a
sense
that won't allow such duplicates?

Thx

ImRe



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Thread
UNIQUE KEY vs NULLsimre11 Dec
RE: UNIQUE KEY vs NULLsemierzwa11 Dec
Re: UNIQUE KEY vs NULLsDan Buettner11 Dec
  • RE: UNIQUE KEY vs NULLsimre12 Dec
Re: UNIQUE KEY vs NULLsMartijn Tonies11 Dec