#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };
use experimental qw{ signatures };

use DBI;

sub run_do($dbh, $id, $name) {
    $dbh->do(qq{
        INSERT INTO customers
        (id,name)
        VALUES('$id','$name')});
}

sub run_select($dbh) {
    my $sth = $dbh->prepare('SELECT * FROM customers');
    $sth->execute;
    while (my @row = $sth->fetchrow_array) {
        say "@row";
    }
}

my %connection = ('dbi:SQLite:dbname=:memory:' => ["", ""],
                  "dbi:Pg:dbname=$ENV{USER}" => [$ENV{USER}, ""]);

for my $dbcs (keys %connection) {
    my $dbh = 'DBI'->connect($dbcs, @{ $connection{$dbcs} });
    $dbh->do('CREATE TABLE customers (id INTEGER, name TEXT)');

    run_do($dbh, 1, 'John');
    run_select($dbh);

    my $id = q{42', 'Batman'); DROP TABLE customers; -- };
    run_do($dbh, $id, 'Joe');
    run_select($dbh);
}

##</code><code>##

1 John
1 John
42 Batman
1 John
DBD::Pg::st execute failed: ERROR:  relation "customers" does not exist
LINE 1: SELECT * FROM customers
                      ^ at ./1.pl line 18.
DBD::Pg::st fetchrow_array failed: no statement executing at ./1.pl line 19.

##</code><code>##

    $dbh->do(join "",
             'INSERT INTO customers(id,name) VALUES(',
             $dbh->quote($id), ', ',
             $dbh->quote($name),
             ')');