package DataTable;
use Moose;

has 'tablename' => (is => 'rw', isa => 'Str', required => 1);
has 'columns'   => (is => 'rw', isa => 'ArrayRef[Str]', default => sub {  [] });
has 'indices'   => (is => 'rw', isa => 'HashRef[Str]',  default => sub { +{} });
has 'datatypes' => (is => 'rw', isa => 'ArrayRef[Str]', default => sub {  [] });

has [qw/ lengths decimals signed allownull default usequote /] =>
    (is => 'rw', isa => 'ArrayRef[Int]', lazy => 1, default => sub { [] });

1;

##</code><code>##

package DataTable;
use Moose;

has 'tablename' => (is => 'rw', isa => 'Str', required => 1);
has 'columns'   => (
    traits  => [ 'Array'],
    is      => 'rw', 
    isa     => 'ArrayRef[Str]', 
    default => sub { [] },
    handles => {
        'add_column'           => 'push',
        'remove_column_at_idx' => 'delete',
        # ... and many more 
    }
);

# rest of the class snipped off for brevity ...

##</code><code>##

my $dt = DataTable->new;

$db->add_column( 'foo' );
$db->add_column( 'bar' );

# columns is now [ foo, bar ]

$db->remove_column_at_idx( 0 );

# columns is now [ bar ]