#!/usr/bin/perl
use warnings;
use strict;

use DBI;

my $db_file = '1.db';
unlink $db_file;

my $db = 'DBI'->connect("dbi:SQLite:dbname=$db_file", q(), q());

# Create the tables.
$db->do($_) for
    'CREATE TABLE user_tbl   (id INT, name   VARCHAR(5))',
    'CREATE TABLE topic_tbl  (id INT, topic  VARCHAR(6))',
    'CREATE TABLE detail_tbl (id INT, detail VARCHAR(7), name_id INT, topic_id INT)';

# Populate the tables.
for my $insert (
                [ 'user_tbl',   [ 1, 'test1' ],  [ 2, 'test2' ] ],
                [ 'topic_tbl',  [ 1, 'topic1' ], [ 2, 'topic2' ] ],
                [ 'detail_tbl', [ 1, 'detail1', 1, 1 ],
                                [ 2, 'detail2', 1, 2 ],
                                [ 3, 'detail3', 2, 1 ] ],
               ) {
    my $table = shift @$insert;
    my $sql = "INSERT INTO $table VALUES ("
            . join(', ', map '?', 0 .. $#{ $insert->[0] }) . ')';
    my $sth = $db->prepare($sql);
    $sth->execute(@$_) for @$insert;
}

# Extract the information.
my $query = << '__SQL__';
    SELECT d.detail, u.name, t.topic
    FROM detail_tbl AS d
    JOIN user_tbl   AS u ON u.id = d.name_id
    JOIN topic_tbl  AS t ON t.id = d.topic_id
__SQL__

my $sth = $db->prepare($query);
$sth->execute;
while (my @row = $sth->fetchrow_array) {
    print "@row\n";
}