In an RDF database, a named graph is what we call a subset of our data that has been given a unique label (name). A graph database can contain any number of named graphs alongside its default graph, and each fact can be present in or absent from any graph.
Suppose we have the following company data in the named graph :OfficialRecords
And the following data in the named graph :SurveyAnswers
We can combine the knowledge in both graphs to find the hobbies of the software developers in this company:
We can also use a variable in place of a graph name to return all the information about the employees: