Example: Generating NIDs

Consider the following new document. The first paragraph can get any NID:

    First paragraph.  (01)
                        

Suppose you added a new paragraph. The first paragraph retains its NID, while the second paragraph gets a new, unique NID:

    First paragraph.  (01)

    This is the second paragraph.  (02)
                        

Now suppose you deleted the second paragraph, and then added a new one. Because the second paragraph was removed, its NID cannot be reused:

    First paragraph.  (01)

    This is the third paragraph added.  (03)