Indeed.

If this were twenty-five years ago, when:

• “Google” was a very big number and nothing more, and ...
• People actually went to libraries, and ...
• Libraries had card-catalogs ...

then I would suggest the analogy that “the book itself” is over there on the shelf, while “the index card or cards that refer to that book” are right here in the various drawers.   Many cards may refer to the same book, and you can make more such cards any time you like (with the librarian’s permission, of course...), but there will still be only one book.

You can build arbitrary data structures in Perl ... but what you are actually doing is moving-around those index cards, not the books themselves.   Perl will take you directly to the book when you use an index-card that refers to it.   Just remember that several cards can refer to the same book, and clearly keep in mind the difference between “the book” and “the card.”

You might think of it as a Hogwarts index-card, though, because if you scribble on the index-card, a mark magically shows up on the book, and therefore every other index-card simultaneously shows the mark.   Be careful when fooling around with magic.