Given this data structure:

$user_master = array ('user_id'=>'user_id',                                         'user_name'=>'requester',                                                                                 'user_login'=>'login_name',                                                                                'user_region_id'=>'user_region');

$user_master['links']['user_region_id']='region_master["region_id"]';

The idea is to have one or more entries to relate certain db fields to other tables. If $tbl='user_master and $key='user_region_id', then if I do this:

if (array_key_exists('links', $$tbl))...
I get a true response. The key exists.

However, I cannot access the values using any of these contructs:

$value=$$tbl['links'][$key]
$values=array_values ($$tbl['links'])
if (array_key_exists($key, $$tbl['links'])
etc. etc.