package MyApp::Ticket;
use strict;

my @_args = qw( time trade_ref adr_buyer_bank adr_seller_bank seller_p
+ays );
my @_atts = map { '_' . $_ } @_args;

sub new {
  my ($class, %args) = @_;
  my $self = bless {}, $class;
  # if constructor has been passed a db handle and a ticket number,
  # get attributes from database. otherwise, get them from args
  my ($dbh, $ticket) = @args{ qw( dbh ticket ) };
  if( $dbh && $ticket ) {
    $self->load( $dbh, $ticket );
  } else {
    @{$self}{ @_atts } = @args{ @_args };
  }
  return $self;
}

sub load {
  my ($self, $dbh, $ticket_number) = @_;
  my $sql = "SELECT * FROM tickets WHERE id = ?";
  my $sth = $dbh->prepare($sql) or die $dbh->errstr;
  $sth->execute($ticket_number);
  my $row = $sth->fetchrow_hashref;
  @{$self}{ @_atts } = @row{ @_args };
}
[download]

I'd opt for polymorphic constructors. You're initializing the same fields two different ways, from two different sources. Let your constructor examine the object being passed in; if it's a database handle, use that, and if not, see if it has the fields you want.

Here's a simple sketch:

package MyApp::Ticket;
sub new
{
    my ($class, $from, $extra) = @_;
    if (UNIVERSAL::isa($from, 'DBI'))   # it's a DB handle
    {
       my $sth = $from->prepare(...);
       $sth->execute($extra);
       # and so on
    }
    else
    {
       $self->{_time} = $from->{time};
       # etc.
    }
    bless $self, $class;
}

#  Called like so:

my $dbh = DBI->connect(...);
my $dbticket = MyApp::Ticket->new($dbh, $ticketno);

# or like so:
my %args;
my $ticket = MyApp::Ticket->new(\%args);
[download]

Update
Better to use isa() instead of can().

package MyApp::Ticket;
use strict;

sub new 
{
    my ($class,%args) = @_;
    
    my $self = bless {};
    
    if ( $args{ticket_number} )
    {
        $self->load( $args{ticket_number} );
    }
    else
    {
        $self->init(%args);
    }
    
    return $self;
                
}

sub init
{
    my ($self,%args) = @_;    
    
    $$self{_time}                 => $args{'time'};
    $$self{_trade_ref}             => $args{'trade_ref'};
    $$self{_adr_buyer_bank}        => $args{'adr_buyer_bank'};
    $$self{_adr_seller_bank}    => $args{'adr_seller_bank'};
    $$self{_ti_seller_pays}        => $args{'seller_pays'};
    
    return $self;
}

sub load 
{
    my $self = shift;
    my $ticket_number = shift;
    
    #
    #    pull the $dbh from some shared location
    #    like a singleton factory
    #
    my $dbh = GetDBH();
    
    my $sql = "SELECT * FROM tickets WHERE id = ?";
    my $sth = $dbh->prepare($sql) or die $dbh->errstr;
    $sth->execute($ticket_number);
    my $row = $sth->fetchrow_hashref;
    return $self->init($$row);
}

#
#    and then initialize tickets like so: 
#

my $new_ticket = new MyApp::Ticket(
                          time=>time(),trad_ref=>34567,
                          adr_buyer_bank => 'blah',
                          adr_seller_bank =>'blah,
                          seller_pays => 99.99
                  );
                  
my $new_ticket = new MyApp::Ticket( ticket_number => 12345 );
[download]

our $properties = { time            => undef,
                   trad_ref        => undef,
                   adr_buyer_bank  => 'test',
                   adr_seller_bank => undef,
                   seller_pays     => undef,                   
                 };
sub new {
    my $class = shift;
    my $self = {};
    map { $self->{$_} = $properties->{$_} } keys %$properties;
    bless $self, $class;
    $self->_init(@_);
    return $self;
}

sub _init {
    my $self = shift;
    if(@_) {
        my %args = @_;    
        map { $self->{$_} = $args{$_} if exists $self->{$_} } keys %ar
+gs;
    }

    $self->{__dbh} = DBI->connection(...) unless defined $self->{__dbh
+};
}

sub load {
    my $self = shift;
  
    my $sql = "SELECT * FROM tickets WHERE id = ?";
    my $sth = $dbh->prepare($sql) or die $dbh->errstr;
    $sth->execute($ticket_number);
    my $row = $sth->fetchrow_hashref;
    
    $self->_init(%$row);
    
    return 1; 
}
[download]

my $ticket = MyApp::Ticket->new();
[download]

my $ticket = MyApp::Ticket->new(time            => time(),
                                trad_ref        => 34567,
                                adr_buyer_bank  => 'blah',
                                adr_seller_bank => 'blah,
                                seller_pays     => 99.99);
[download]

my $ticket = MyApp::Ticket->new();
my $res = $ticket->load(12345);
[download]

      
--------------------------------
SV* sv_bless(SV* sv, HV* stash);