Monday, August 08, 2005

RDF Algebra and Aggregates

* RAL: an Algebra for Querying RDF "RAL is an algebra for RDF defined from a database perspective, some of its operators being inspired by their relational algebra counterparts...Based on the similarities between monads and RAL collections, one can reuse the three monad laws (left unit law, right unit law, and associativity law) as equivalence rules in RAL...RAL operators come in three flavors: extraction operators retrieve the needed resources from the input RDF model, loop operators support repetition, and construction operators build the resulting RDF model." Demonstrates: projection, selection, cartesian product, join, union, difference, intersection, map, Kleene star, create node, create edge, delete node, delete edge, variables and sorting. Part of CognitiveWeb, also has a SPARQL project.
* RDF Aggregate Queries and Views "In this paper, we propose the CAA (Compute Aggregates Algorithm) algorithm to efficiently compute aggregate operations such as COUNT,SUM,AVG,MIN,MAX and so on. CAA can also handle GROUPBY queries. We subsequently define algorithms to maintain aggregate views. These are views involving aggregate queries."
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