Re: Duplicate fields in select_hashref

On Thu, 28 Jan 2010 12:40:00 -0500, Erik Aronesty <[email protected]> wrote:

> The fact that count(*) shows up as "count" in the field name isn't driven by
> DBI - it's driver dependent.

DBD::Pg     - "count"
DBD::Oracle - "count(*)"
DBD::Unify  - "count(*)"
DBD::CSV    - "count(*)"
DBD::SQLite - "count(*)"

So IMHO a bug in DBD::Pg.

> Sybase has it as an "unnamed column" (or at least it used to) ... only way
> to get at it would be with an arrayref!

I don't have DBD::Sybase, but I'd opt for a similar change too

> You shouldn't rely on unnamed derived expression columns having a particular
> name ... and it should not be documented as behaving in a particular way by
> DBI, since drivers might change.

Sure, but this is "dbi-dev" - the *developers* list, where I can stir
the pot and hope to get to some standardisation.

> If you use count(*) ... instead use count(*) as the_count
> .... being explicit will avoid problems.

Unless the DBD (or underlying database) does not support field aliases
My personal point of view is almost always from a portability
standpoint.

For performance reasons, I almost always use bind_columns () and seldom
use fetchrow_hashref ().

> On Thu, Jan 28, 2010 at 12:12 PM, H.Merijn Brand <[email protected]>wrote:
> 
> > On Thu, 28 Jan 2010 11:59:16 -0500, Erik Aronesty <[email protected]>
> > wrote:
> >
> > > Just use the *_arrayref versions for multiple fields with the same name
> > > instead of hashref or slice{}
> >
> > That is what I've shown. Bind_columns () or aliasing also works.
> >
> > > You can't reliably refer to fields by name if they overlap.
> >
> > indeed, which is what I have shown.
> > I'm not complaining here or filing a bug report. I'm probing for
> > opinions in how to document this.
> >
> > I *do* think that count, count (*) mapping to count, count /is/ a bug.

-- 
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