eval { $form->model->create };

    if ($@ =~ /column (\w+) is not unique/) {
        $form->get_field($1)
             ->get_constraint({type => 'Callback'})
             ->force_errors(1);
        $form->process;
    }

##</code><code>##

    eval { $form->model->create };

    if ($e =~ Exception::Class->caught('DBI::Unique')) {
        $form->get_field($e->column)
             ->get_constraint({type => 'Callback'})
             ->force_errors(1);
        $form->process;
    }