>With multiple indexes (or TAGs), each index (or Tag) would have a primary key, right? The primary key is the first "field" in the index key (example CUST+INVOICE, CUST is primary key). The same table, could have a different primary key for each index! Or, it could have the same primary key for a variety of secondary keys (or "sorts").

Terry,

No, that is not correct. A primary key is "a field or group of fields that uniquely indentifies a specific record in the table."