RES: Fabian Pascal and RDBMS deficiencies in fully

What is real data for birthday -> no birthday, n/a in date datatype
representation ?
For mysql is 0000-00-00 and invalid date.
For me is simple null, you have no data to put in the field.

For me null is good in some situation, and bad in ohters.
Just you have to think if you permit or not this value.

Alejandro Michelin Salomon
Porto Alegre
Brasil
-->-----Mensagem original-----
-->De: pgsql-general-owner(at)postgresql(dot)org
-->[mailto:pgsql-general-owner(at)postgresql(dot)org] Em nome de A.M.
-->Enviada em: sexta-feira, 9 de junho de 2006 13:01
-->Para: Postgres general mailing list
-->Assunto: Re: [GENERAL] Fabian Pascal and RDBMS deficiencies in fully
-->
-->
-->On Fri, June 9, 2006 11:45 am, David Fetter wrote:
-->> On Fri, Jun 09, 2006 at 05:20:46PM +0200, Martijn van Oosterhout
-->> wrote:
-->>
-->>> On Fri, Jun 09, 2006 at 07:09:12AM -0400, Agent M wrote:
-->>>
-->>>> Well, the Date argument against NULLs (and he never
-->endorsed them,
-->>>> or so he claims) is that they are not data- they represent the
-->>>> absence of data- so why put non-data in a _data_base.
-->>>
-->>> At this point you could start a whole philosophical
-->discussion about
-->>> whether knowing you don't know something is a fact worth storing.
-->>
-->> And to me, the answer is an unqualified "yes." A state of
-->ignorance
-->> is an important piece of information by itself.
-->>
-->> For example, that I don't know someone's birthdate is
-->important. When
-->> I'm trying to figure out when to send a birthday card,
-->knowing that I
-->> don't know this piece of information means that I take a different
-->> action "decide whether to try to find out what the
-->birthdate is." from
-->> the action I would take if I didn't know that I don't know the
-->> birthdate, which is "rummage through all my records trying
-->to find the
-->> birthdate."
-->
-->So you should normalize and add relations to represent the
-->state adequately. NULL doesn't give you enough information
-->anyway- does NULL in a birthday header mean "no birthday",
-->"n/a" (a business doesn't have a birthday), "not born yet",
-->etc... Using real data, you can represent any of these states.
-->
-->
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