some weeks ago I came across a problem with DELETE IGNORE while using
foreign key constraints on MySQL 5.1.43.
The problem is already known and has been verified, but no fix has been
made to far: http://bugs.mysql.com/bug.php?id=44987
I've supplied a patch (http://bugs.mysql.com/file.php?id=13943&text=1)
which is working quite well for me but somebody with a deeper
understanding of the code should probably double-check it.
Unfortunately it's not assigned to anyone which is why I'm writing to
this list :) I would really like to see this bug fixed in the next
release even though it's only "non-critical".