Change: Blank Nodes in SPARQL Queries

created on Feb. 23, 2013, 9:34 a.m. by Hevok & updated on Feb. 23, 2013, 9:34 a.m. by Hevok

In RDF(S) there are not only URI, Literals and type Literals there are also Blank Nodes. Blank Nodes could not necessary be referred from outside, they especially stand for things that do not really have an existing outside of the Database that stands for some quotation or assertion existence. Therefore one has the possibility to use these Blank Nodes withing a SPARQL Query. For example below one has two prefixes for URI and a SELECT` statement where one here simple selects the Variable Name. Then one has in theWHEREClause, first a reference to a Blank Node in the Subject so in the same way as in RDF. So the Blank Nodes starts with an underscore and one is looking for Blank Nodes that are of Type Lecture. Then again there after the Semicolon the Triple continues and it is said also this Blank Node should have the Propertyis managed by, so it is a Lecture. Then again there is there is a Blank Node at the Object level. Then all things that are connected to the Blank Node in a separate Triple, they have the Brackets around to show that there is again a Blank Node is referring to an Object. And there is a Blank Node that is connected to the Propertyrdfs:label`` and the Name that is here in the Variable. So what is selected here are the Names of the Managers that are identified by a Blank Node.

Again a Blank Node is referring to an Object.

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Categories: Tutorial
Parent: SPARQL

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