Important Notice: Our web hosting provider recently started charging us for additional visits, which was unexpected. In response, we're seeking donations. Depending on the situation, we may explore different monetization options for our Community and Expert Contributors. It's crucial to provide more returns for their expertise and offer more Expert Validated Answers or AI Validated Answers. Learn more about our hosting issue here.

Can I use SPARQL to select a single value based on an ordered list of predicates which might appear in the data?

April 26, 2017appear based Data list ordered predicates select SPARQL value

0

Posted

Can I use SPARQL to select a single value based on an ordered list of predicates which might appear in the data?

1 Answer

0

Posted

When writing SPARQL queries against heterogeneous data sources, one often wants to select a value for a certain purpose without knowing which one of several predicates might be used in the data. The SPARQL OPTIONAL keyword can be used to accomplish this. Suppose we are selecting a human-readable label for a Web page, and we want to use the value of the Dublin Core title predicate (dc:title) if it exists, and otherwise use the value of the rdfs:label predicate.