[Dbix-class] Fastest method to check for key existence?

[QE :: Felix Ostmann]

I often build a map and use this also for an exist()-check (not for bigdata)

my %email_for =
    map { $@_ }
    $rs
        ->search(
            undef,
            {
                select => qw[ user_id email ],
            },
         )
        ->cursor
        ->all
    ;

only important is to use exact 2 fields in the select.



Mit freundlichem Gruß
Felix Ostmann


2015-02-13 12:13 GMT+01:00 Ekki Plicht (DF4OR) <ekki at plicht.de>:

> Ooookay... that's a lot of very helpful answers. Many thanks for all
> the suggestions, I guess I will go with the helper or with count().
>
> Thanks,
> Ekki
>
>
> 2015-02-13 11:32 GMT+01:00 Will Crawford <billcrawford1970 at gmail.com>:
> > On 11 February 2015 at 21:58, Ekki Plicht (DF4OR) <ekki at plicht.de>
> wrote:
> >> Hi,
> >> I need to check a list of values if they exist in a database. The
> >> value is a unique key of that table. A stupid 'find' works of course,
> >> but returns the whole row data, where I only need a simple binary
> >> yes/no information if a row was found or not.
> >
> > Presuming you mean that you need to get a list of them all, there's a
> > few answers, depending on your needs. A couple of the answers already
> > given are pretty useful and I'll be filing the "exists" rs method away
> > for future use.
> >
> > Something like
> >
> >     my %found = map +( $_ => 1 ),
> >         $rs->search_rs( { key => { -in => [ ... ] } }
> )->get_column('key')->all;
> >
> > might do the trick (not tested for typos).
> >
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