At 10:22 PM 2/22/2007, Tim Tassonis wrote:
>Chris wrote:
>>An empty string is a KNOWN value. You know exactly what that value
>>is - it's an empty string.
>>A NULL is UNKNOWN - it doesn't have a value at all.
>
>I do still think it is a bit of an oddity, the concept of the null
>column. From my experience, it creates more problems than it
>actually solves and generally forces you to code more rather than
>less in order to achieve your goals.
>
>But as it is a fundamental, defined part of the sql standard, one
>just has to live with it.
Well it can be useful to have a column like:
foo integer not null default null
That means someone/something must specify a value for foo when doing
an insert. They can't just hope for the best that there's a default...
I think that works on postgresql but not on MySQL (see back on topic :) ).
Have fun!
Link.
