I think that what you want is a new TO on your relationship graph - it might be named "ChildTableFKtoGlobalPK".
The global key would be in one table (say, the parent table), and would be related to the child table.
Perhaps you can explain what you are trying to accomplish through such a structure. There might well be a better way to do it.
If I did that would the field that is global change for all records in the table?
all fk's = a collection
If I have 6 members in the collection and one is the "MAIN" (most important) to the information. However this changes many times. And I want numbering to adjust to the change. Thanks
yes - the global field is truly global across the entire DB .. all tables.
Addendum: globals are machine-specific - not shared among users.
A little more ...
if your "normal" relationship is "Order::pk_OrderNumber <--> LineItem::fk_OrderNum", then the new TO related by g_OrderNumber to the LineItem table might be "Order::g_OrderNumber <--> LineItem::fk_OrderNum".
So do I understand correctly that within a collection there is one record that is the primary or "Main" record and you may be working with multiple collections?
When you say this "changes many times" - how do the changes happen? Through scripts? By user interaction?
And when you say you want the numbering to adjust, what do you mean? The numbering of the items in a portal?
One option that comes to mind is that you could flag one of the records as being the primary record. Then if you have your relationship sorted by the flag field, you could set it up so that the first record is the primary record. This would change the numbering in a portal and also allow you to fairly easily access the information from that primary record.
However, I still feel as though I don't completely understand what you are trying to do.
The way I read this, you just need a field in the parent table to function as your "global".
If you have Parent----<Children
To save a value that is "global" to just a given set of "children" with the same match field value to Parent, put the field in the parent record. You change it once there and all children will see the new value, but only for the children related to that parent.