Support importing uc address records with migrate.module

Have you used migrate.module at all? The problem with UIDs is as follows:

- Your legacy site probably has its own customer_id fields or whatever in its address book.

- Part of migrating from your old site to Drupal will convert the legacy customers into Drupal users. This will result in a {migrate_map_N} table that maps legacy.customer_id to drupal.uid values for all the migrated users.

- So, when you then go to import the address book records into Drupal, you want to import them using the Drupal UID, not the legacy customer_id.

However, until #610128: Can't add external and internal tables' columns to the same view is resolved, you can't actually add a relationship to one of your table wizard views so that your legacy {address_book} table can JOIN on the {migrate_map_N} table in your Drupal site to map the customer ids.

Therefore, to make this work, you need to do a bit of extra processing, define hook_migrate_prepare_uc_addresses(), and do a little query to map the legacy customer_id into the Drupal uid. Something like this:

/**
 * Implement hook_migrate_prepare_uc_addresses().
 *
 * Fills in the appropriate UID based on the user migration map, sets
 * is_default properly, handles the address nickname, and maps the
 * country code into the {uc_countries} country_id.
 */
function foo_migrate_prepare_uc_addresses(&$address, $tblinfo, $row) {
  // The map of legacy customers to Drupal users just happens to be map #4 on my site.
  // In general, this will be different for your site.
  $query = db_query("SELECT destid FROM {migrate_map_4} WHERE sourceid = %d", $address->uid);
  $address->uid = db_result($query);
  $address->is_default = ($row->address_book_id == $address->is_default);
  if ($address->is_default) {
    $address->address_name = 'default';
  }
  else {
    $query = db_query("SELECT COUNT(*) FROM {uc_addresses} WHERE uid = %d", $address->uid);
    $address->address_name = $address->first_name . ' ' . $address->last_name . ' #' . db_result($query);
  }

  $query = db_query("SELECT country_id FROM {uc_countries} WHERE country_iso_code_3 = '%s'", $address->country);
  $address->country = db_result($query);
}

This also handles smart nicknames for the imported addresses, and maps the source data country from ISO 3 country codes into the {uc_countries} integer code that {uc_addresses} expects... Mapping countries is somewhat complicated -- see #627866: Introduce concept of field formatters or conversion handlers? and #626380-1: Add migrate.module support for uc_order (orders, order product details, etc) for more...

Anyway, yeah, I can put a link to this issue into the README with instructions about using migrate.module, since this is now pretty decent documentation. ;)

Right. I'm doing an osCommerce migration now. There didn't exist a great migration strategy as of a week ago, either, but I'm writing it ;)

#620812: Support importing UberCart product fields with migrate.module
#626380: Add migrate.module support for uc_order (orders, order product details, etc)
...

There's interest, see #850180: Ubercart + Migrate Module - Working module attached. for example. I'd appreciate it if you didn't close things that aren't actually done. ;) Thanks.

Although, in fairness, I'm not working on this now, so unassigned is more accurate... ;)