On Fri, Sep 24, 2010 at 11:55 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Fri, Sep 24, 2010 at 11:43 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> -1. There's nothing wrong with the function-as-a-computed-column
>>> feature, and it seems likely that taking it away will break applications.
>
>> ... What evidence do we have that anyone is relying on this
>> behavior in applications? Every report I've heard of it involved
>> someone being surprised that it worked that way.
>
> So? There are lots of surprising things in SQL. And *of course* the
> only complaints come from people who didn't know about it, not from
> satisfied users.
I guess that's true, but is this behavior specified in or required by
any SQL standard? Are there other database products that also support
this syntax? Or is this just our own invention?
> The reason people don't know about this feature is that it's so poorly
> documented --- there's just one mention buried deep in chapter 35 of
> the manual, in a place where most people wouldn't think to look for it.
> I'm not quite sure where's a better place though.
I think it's because it's counterintuitive.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company