| From: | "Massa, Harald Armin" <harald(at)2ndquadrant(dot)de> |
|---|---|
| To: | Phoenix Kiula <phoenix(dot)kiula(at)gmail(dot)com> |
| Cc: | PG-General Mailing List <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: NULL saves disk space? |
| Date: | 2011-04-28 14:08:45 |
| Message-ID: | BANLkTimP6GZ2HcMB51Uv3YtsBgMHjWRUyg@mail.gmail.com |
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| Lists: | pgsql-general |
>Do I save disk space by having them as NULL instead of FALSE? So my >application would have conditional code for NULL and TRUE, instead of >FALSE and TRUE.
The short answer:
do not even think about it.
NULL has a well defined meaning within SQL: "we do not know the
value", with "well defined" being something totally different from
"intuitive".
With "using NULL as false" you woud get:
select whatever from yourtable where not (booleancolumn = true )
would result in ....wait for it .... zero rows.
Because "NULL" is not "not =" to true.
There is no potential diskspace saving in the world that could be
worth those troubles.
Harald
--
Harald Armin Massa www.2ndQuadrant.de
PostgreSQL Training, Services and Support
2ndQuadrant Deutschland GmbH
GF: Harald Armin Massa
Amtsgericht Stuttgart, HRB 736399
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