Re: postgresql vs mysql

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От Ben
Тема Re: postgresql vs mysql
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Msg-id 77F71D84-9A0D-4D20-ABE7-488B886372AD@silentmedia.com
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Ответ на Re: postgresql vs mysql  (Glen Parker <glenebob@nwlink.com>)
Ответы Re: postgresql vs mysql  ("Joshua D. Drake" <jd@commandprompt.com>)
Re: postgresql vs mysql  (Tommy Gildseth <tommy@gildseth.com>)
Re: postgresql vs mysql  (Glen Parker <glenebob@nwlink.com>)
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I'm sorry maybe I missed something, but if you don't need NULLs and
feel they just add extra work, why don't you just declare all your
columns to be not null and have them default to zero or an empty string?

On Feb 22, 2007, at 5:11 PM, Glen Parker wrote:

> Buy the same token, some application have no use whatsoever for the
> distinction between NULL and ''.  In that case, the distinction
> just adds work.
>
> I would love to see different ways to handle NULL implemented by
> the server.  For what I do, NULL could always compare equal to zero
> and ''.  I have no use for NULL in text values.  I do need it for
> numerics, however it doesn't mean "unknown", it just means "not
> entered", which is different because I always treat it as zero.
>
> I haven't put enough thought into this to make any sort of
> comprehensive proposal, but it occurs to me that perhaps it could
> be integrated into the type system.  If I were able to specify, for
> any given type, a value that should compare equal to NULL ('' for
> varchar, 0 for int4, for example), that, in combination with NOT
> NULL constraints, might just do it for me.
>
> -Glen
>
>> Well, your mileage must vary. The absence of nulls would make my life
>> difficult.
>> Just substitute "unknown" for "null" as mentioned above and the
>> various
>> operations with "null" make sense. For example, take some days and
>> low-temperatures:
>> Mon: 30
>> Tue: 10
>> Wed: 0
>> Thu: unknown
>> Fri: 0
>> Sat: unknown
>> Sun: -5
>> Was the low temperature the same on:
>> Mon/Tue: no
>> Wed/Fri: yes
>> Thu/Fri: unknown
>> Thu/Sat: unknown <- the always seemingly confusing null=null is null.


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