use PerlTypelessAutovivifyingDB;

my $dbh = PerlTypelessAutovivifyingDB->opendb() or die $!; # open master database file, location set on PerlDB module install

my $db = $dbh->db('animals'); # use database 'animals', create it if it doesn't exist

my $table = $db->table('cats'); # use table 'cats', create it if it doesn't exist

$table->key('name'); # alter table to make column 'name' a unique key, permanently

my @cats = ( { 'name' => 'lucy',  'age' => 2,  'species' => 'lion' },
             { 'name' => 'mary',  'age' => 5,  'species' => 'lion' },
             { 'name' => 'cindy', 'age' => 10, 'species' => 'tiger' }
           )

foreach my $cat (@cats) {
    $table->set(%$cat); # insert or update entry represented by hash into table.
                        # any non-existant columns are autovivified in the table like in hashes
                        # IF hash assigns a unique key column an existing value
                        #    update that entry
                        # ELSE
                        #    insert new entry, set any key columns to a new unique value (eg first available integer)
}

my $sth = $table->select { $a{'species'} eq 'lion' } ('name', 'age'); # prepare and execute select name and age where species is lion;

foreach (my ($name, $age) = $sth->fetchrow_array()) {
    print "$name ($age years), ";  # print 'lucy (2 years), mary (5 years)'
}

$sth->finish();

my $joinedtable = $db->table {  $a{'cats.name'} eq $b{'kittens.mothersname'} } ('cats','kittens'); # join two tables on cats.name == kittens.name

my $sth2 = $table->select ('cats.name', 'kittens.name'); # default to leftmost table name in column name conflict

foreach (my ($name, $kitten) = $sth2->fetchrow_array()) {
    print "$name has a kitten $kitten.  ";
}

$sth2->finish();

# database automatically closes itself on block exit