Blank node

In RDF, a blank node (also called bnode) is a node in an RDF graph representing a resource for which a URI or literal is not given. The resource represented by a blank node is also called an anonymous resource. According to the RDF standard a blank node can only be used as subject or object of an RDF triple. In RDF, a blank node (also called bnode) is a node in an RDF graph representing a resource for which a URI or literal is not given. The resource represented by a blank node is also called an anonymous resource. According to the RDF standard a blank node can only be used as subject or object of an RDF triple. Blank nodes can be denoted through blank node identifiers in the following formats, RDF/XML, RDFa, Turtle, N3, N-Triples, and RDFa.The following example shows how it works in RDF/XML. The blank node identifiers are only limited in scope to a serialization of a particular RDF graph, i.e. the node _:b in the subsequent example does not represent the same node as a node named _:b in any other graph. Blank nodes can also be denoted through nested elements (in RDF/XML, RDFa, Turtle and N3). Here is the same triples with the above. Below is the same example in RDFa. Below is the same example in Turtle. Blank nodes are treated as simply indicating the existence of a thing, without using a URI (Uniform Resource Identifier) to identify any particular thing. This is not the same as assuming that the blank node indicates an 'unknown' URI.