MySQL Bugs: #11907: Duplicate entry NULL for key

Bug #11907	Duplicate entry NULL for key
Submitted:	13 Jul 2005 10:04	Modified:	30 May 2013 5:22
Reporter:	ilias iliadis	Email Updates:
Status:	Can't repeat	Impact on me:	None
Category:	Connector / ODBC	Severity:	S3 (Non-critical)
Version:	4.0.20-log	OS:	Linux (Mandrake 10.1)
Assigned to:		CPU Architecture:	Any

Description:
From time to time, in the same server but in different databases, VB program (connecting through MyODBC 3.51, vb6 with service pack 6 for vb6, with a public ADODB.Connection) reports error "Duplicate entry NULL for key foo" and the key is not unique and already has millions (almost all) records that are NULL. After passing a value in that key the subsequent INSERTs are accepted.
It comes after one year in mandrake 8.0 and mysql 3.23 (were it never happened) we upgraded to mandrake 10.1 and mysql 4.0.20-log and after 3 months happened once. INSERTing some records with (false for our data). After some days we hade the same problem with the same solution but for another key. And after some days in another database.The strange thing is that (as I stated all the tables already contain millions of records having NULL values in that key)

How to repeat:
The bug cannot be repeated since it is not repeatable.

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

Not enough information was provided for us to be able to handle this bug. Please re-read the instructions at http://bugs.mysql.com/how-to-report.php

If you can provide more information, feel free to add it to this bug and change the status back to 'Open'.

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