The json data that I am importing is exported from a site using Drupal6. In the orginial code Drupal considered this to be a taxonomy but in WordPress it is a simple text field as are the other two meta fields. The WordPress site uses the wp API (v2) to display the post data on the front end for reasons that are a bit complicated to explain 😉
I take your point that the field key is required though. So I take it I should retrieve the field keys of each of the fields in question and also update them in my import function?
update_post_meta( $post_id, _{$field_name}, $field_key )
