Mapping taxonomy terms from Drupal 5 to Drupal 7

In Drupal 7 tagging terms are stored as fields of the entity. In previous Drupal versions tags are assigned to nodes stored in a table taxonomy_index(nid, tid, created). In D7 we have some table as for example field_data_field_taggings were each term refrerence is stored as a row. If more then one term is assigned to a content node (e.g. in the answers module), the value in the column delta incremented to have a unique key. To generate this table we need an sql statement that increments this delta if more than one term exist for the node.