>Do I save disk space by having them as NULL instead of FALSE? So my >application would have conditional code for NULL
andTRUE, 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
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