As I know, REF no is specific name of item (such as your ID), this was created automatic, it is only and unchangeable. Item in PDMS linked by ref no instead name, so if you change item's name, they still link. Some time, you include db from other database, item's name may be doublicated, if you type name in command line, PDMS will go to the fist item have this name in DBs, but if you type REF no in command line PDMS will focus to exactly item that you want to.
Every element has a reference number, which is assigned when the element is created, and is unique to that element within the project.
The reference number comprises two 32 bit integers. This is displayed in the form:
=1234/6789
The first integer encodes the database number. This can be queried on the command line using Q DBNUMBER.
The second integer is a sequence number, starting at 0, and incrementing each time an element is created.
Thus, for example, the element with a reference number of =8193/0 will be the WORLD element (since this is always created first) created in DB 1.
The reference number is never changed once an element has been created.
