The W3C Resource Description Framework (RDF) is gaining popularity for its ability to manage semi-structured data without a predefined database schema. So far, most RDF query processors have concentrated on finding complex graph patterns in RDF. which typically involves a high number of joins. This works very well to query resources by the relations between them. Yet, obtaining a record-like view on the attributes of resources, as natively supported by RDBMS, imposes unnecessary performance burdens, as the individual attributes must be joined to assemble the final result records. We present an approach to retrieve the attributes of resources efficiently. We first determine the resources in question and then retrieve all their attributes efficiently at once, exploiting contiguous storage in RDF indexes. In addition, we present an index structure which is specifically designed for RDF attribute retrieval. Our measurements show that our approach is clearly superior for larger numbers of attributes.
展开▼
