You can easily convert between arrayref and hashref.

If converting between arrays and hashes is problematic for you, maybe you should review your Perl learning material or program some exercises about how to convert between an array and a hash (and a hash and an array).

For example, you might have this array:

#!perl -w
use strict;

#               Name Age Street
my @user = (qw(John 42  Infinityway));
my %user = ...;
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How would you convert the data from @user (an array) to a hash (%user)?

The names are easier for you to understand. your previous code used hashs.

and what effective difference does it make, just how many rows are going to come back from that select? "use DBI;" probably cost more than hashref for this query.