If I understand the question (and your subsequent clarification) correctly, I think this should do the trick:

use strict;
use warnings;

use DBI;
use DBD::SQLite;
use Data::Dumper;

my $dbh = DBI->connect(
    'dbi:SQLite:dbname=test.sqlite',
    undef, undef, { RaiseError => 1, PrintError => 1, } );

eval {
    $dbh->do('CREATE TABLE evkeypairs (id INTEGER PRIMARY KEY NOT NULL
+,key TEXT,value TEXT);');
    $dbh->do(q!INSERT INTO evkeypairs (key, value) VALUES ('foo','bar'
+);!);
    $dbh->do(q!INSERT INTO evkeypairs (key, value) VALUES ('kung','foo
+');!);
} or warn "$@";

my $sth = $dbh->prepare( 'SELECT * FROM evkeypairs' );
$sth->execute;
my $href = $sth->fetchall_hashref( 'id' );

print Dumper $href;

$dbh->disconnect;
unlink 'test.sqlite';
__END__
$VAR1 = {
          '1' => {
                   'value' => 'bar',
                   'id' => '1',
                   'key' => 'foo'
                 },
          '2' => {
                   'value' => 'foo',
                   'id' => '2',
                   'key' => 'kung'
                 }
        };
[download]

Thanks to AM for providing the code to create a test db.