Re: more on execute_array not complying with the specification

On Tue, Feb 01, 2011 at 09:02:26PM +0000, Martin J. Evans wrote:
> On 01/02/2011 20:50, Tim Bunce wrote:
> >On Tue, Feb 01, 2011 at 10:58:14AM -0500, John Scoles wrote:
> 
> >>My only concern is when it does error (no matter what the setting of
> >>AutoCommit) you always get unef;
> >Umm, yes. Returning undef (or an empty list) if there was any kind of
> >error causes useful information (the total row count) to be discarded.
>
> I don't see why when called in list context. Just because
> execute_array partially succeeded (or failured) only means undef
> needs to be returned for the first scalar and does not affect the
> rows affected.

True for the total row count. I was thinking of the RaiseError case,
I think. Also, by that definition, this wouldn't work:

    unless (($tuples, $rows) = $sth->execute_array(...)) {
        ...handle error...
    }

That's not a big deal though.  (Returning undef for the tuple count
isn't a big problem because you can determine that from the length of
ArrayTupleStatus.)

> >This brings us back to the question of whether a failure of a single
> >tuple should cause execute_array() itself to return an error.
> >
> >ODBC doesn't do that. It treats that situation as SUCCESS_WITH_INFO
> >and that does seem very reasonable.
>
> The funny thing is being an big user of ODBC, I don't (and others in
> this thread expressed the same belief).

I'm (wobbling) on the fence on that one. I can see it both ways,
though I'm more sympathetic to your viewpoint :)

> For me, if I use execute_array (with AutoCommit on or not) my
> principle issue is I want to know if anything failed so I do:
>
> $dbh->{RaiseError} = 1;
> my $ret = eval {
>    execute_array(...)
> };
> do_something_on_error() if ($@ || !$ret); # amended for DBD::Oracle behavior

Ok. How would you get the total row count when using RaiseError?

> Why put the onus on people who cannot accept some tuples to fail to
> check the ArrayTupleStatus instead of put it on those who can accept
> some to fail to examine ArrayTupleStatus? My feeling is that it is
> very serious to ignore a partial failure and so the default should
> be to ensure you know about it with RaiseError. For those people who
> can accept a tuple to fail, they can look at ArrayTupleStatus and
> still commit the changes.

I agree.

> >>but I can live with that.
> >Perhaps we could default to the SUCCESS_WITH_INFO model and add an
> >attribute for people to use if they want tutple errors to cause
> >execute_array() itself to return an error.
> >
> >We can debate the name later, but for now let's call it:
> >
> >     ArrayPromoteTupleError =>  1
>
> which defaults to 1, I hope.

Probably ;-)

> Incidentally, I just blogged about this a few hours ago as I think
> it is a serious problem to ignore potential failures. Add that to
> the fact that some versions of Oracle database (broken) return
> success with info but don't then commit the ok tuples.

Yes, that's clearly a serious bug.

Tim.