I'm trying to force a parallel identifier (to match up legacy system requirements) to correlate to
uid by means of a
field_data_field_foo was created in the Field UI and because I couldn't see any
AUTO_INCREMENT options I set them both for the column
field_data_field_foo.field_foo_value in phpMyAdmin.
I assumed this would be enough to force the issue, but in development I setup a
hook_user_presave() function in my custom module and with a break point inside it, for
$account->field_foo I just get undefined....
field_foo Array  und Array 
Because this is something that must be assigned uniquely and I'd like to assign at the point of registration should I be using a different hook? Or is there something else I'm missing?
Btw, it might be something more basic in Drupal that I'm missing as I'm not that experienced with it atm - i.e. due to the nature of this project, I've yet to spend time learning nodes and the like.