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rdfblank-nodes

Blank node in RDF

I just started learning about RDF and my question is: What is the purpose of the blank node?

Example:

ex:John   foaf:knows       _:p1
_:p1      foaf:birthDate   04-21

This means that John knows someone who is born on 04-21.

But I can't understand the purpose.

Solution

  • For your simple example the reason for the blank node would be that you do not know anything else about this person born on 04-21, except that John knowns him or her. You have insufficient knowledge to give him/her a proper URI and simply add the two known statements.