Re: NULL vs. Empty String

On Wed, 14 Mar 2001, Oliver Elphick wrote:

> You could write a rule for each table/column that would substitute
> NULL for ''.
>
> However, the concept is all wrong. NULL means "I don't know what
> this value is". '' means "I know that this value is an empty string".
> Furthermore, having NULLs in columns means you have to be careful
> to use ternary logic for every condition (because NULL=x is neither
> true nor false).

And On Wed, 14 Mar 2001, Steven Lembark wrote:

> Postgress is doing what you want it to -- see anything CJ Date
> has written in the last 20 years. you are better off inserting
> a default value of '' than NULL -- otherwise you have no idea
> what joins mean.

I completely agree with you two that PostgreSQL does The Right Thing (TM)
vs. what Oracle does. Thus, perhaps I should shift the focus of my queries
to the mod_perl list, since I think it makes sense that empty form fields
submitted from a web page should show up in Perl as undefined (and
therefore will be inserted into Postgres as NULL) rather than as empty
strings.

Thanks for the feedback.

David