my %TABLES = (      # Hash identifying one database
  'users' => [      # Hash keys are the database's tables
    'username',
    'password',     # Columns of the table in an array
    'first_name',
    'email_address',
    'rating'
  ]
);

##</code><code>##

$handle->insert (
  -table        =>  "users",
  -primary_key  =>  "username",
  -values       =>  { 
    username      =>  "mt2k",
    first_name    =>  "Nathan",
    email_address =>  'email@example.net',
    password      =>  crypt("password", $salt),
    rating        =>  10
  }
);

##</code><code>##

sub insert {
  my ($self, %q) = @_;

  # Set up placeholders
  my $ph = join ', ', ('?') x values %{$q{'-values'}};

  # Prepare the query for the database
  my $sth = $self->{DB}->prepare(
    "INSERT INTO $q{'-table'} VALUES($ph)"
  );

  # This is the line that causes problems. Read below for more.
  $sth->execute(values %{$q{'-values'}});