has 'columns'     => (is => 'rw', isa => 'ArrayRef[Str]',                  lazy_build => 1,);
has 'datatype'    => (is => 'rw', isa => 'ArrayRef[Str]',                  lazy_build => 1,);
has 'decimals'    => (is => 'rw', isa => 'ArrayRef[Maybe[Int]]',           lazy_build => 1,);
has 'default'   => (is => 'rw', isa => 'ArrayRef[Maybe[Value]]',         lazy_build => 1,);
has 'flatfield_start'  => (is => 'rw', isa => 'ArrayRef[Maybe[Int]]', lazy_build => 1,);
has 'flatfield_length' => (is => 'rw', isa => 'ArrayRef[Maybe[Int]]', lazy_build => 1,);