Re: Best practices for "Gender Column"

From: joel garry <>
Date: Tue, 7 Jul 2009 14:35:07 -0700 (PDT)
Message-ID: <>

On Jul 7, 2:15 pm, "Matthias Hoys" <> wrote:
> "jose" <> wrote in message
> > This days, I'm participating in the design of a new application for a
> > Biotechnology company. I found the following:
> > -In some applications they use for (Gender/sex column) NUMBER(1) and
> > this could be Null because in some cases they don't know the Gender
> > until they get the genotype, but in this applications the values are
> > (1 = Male , 2 = Female and Null ), the problem with this solution is
> > that in some cases when the people is reading the information always
> > is asking 1 is for male o for female ?
> > -In the new application I suggest to use VARCHAR2(1) for this column
> > and this must be NOT NULL, and the possible values must be M=Male
> > F=Female and U= Unknown. I think is better use a value against a Null
> > because of the indexes, I mean in case we decided to index by this
> > column the null values will never be indexed.
> > I'm posting this to here any comments, thanks, Uriel.
> Looks ok to me, you could then add a check constraint to the column (add
> CONSTRAINT gender_name CHECK (gender IN ('M','F','U')) and you could add a
> foreign key constraint to a "gender" table, with the varchar2(1) column as
> PK constraint and an additional column that describes the gender type.
> But what about hermaphrodite organisms? ;-)
> Matthias

And of course, what if the genotype doesn't match the phenotype? And the phenotype is malleable... as always, it depends on deeper requirements analysis.


-- is bogus.
Received on Tue Jul 07 2009 - 16:35:07 CDT

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