I am trying to make a select box for Woocommerce categories on another custom post type. I am using the code below but it doesn’t appear to be saving in the database … actually I cant find categoryreq in the database which I assumed I would find in the wp_terms table. Can you tell me how to do this?

I was using this page for reference — https://piklist.com/user-guide/tutorials/display-taxonomies-as-a-dropdown-or-radio-buttons/

piklist('field', array(
    'type' => 'select'
    ,'scope' => 'taxonomy'
    ,'field' => 'categoryreq'
    ,'label' => 'Categories'
    ,'description' => 'Terms will appear when they are added to this taxonomy.'
    ,'choices' => piklist(
      get_terms('product_cat', array(
        'hide_empty' => false
      ))
      ,array(
        'term_id'
        ,'name'
      )
    )
  ));