Contemporary XPath query engines evaluate queries in time exponential in the sizes of input queries, a fact that has gone unnoticed for a long time. Recently, the first main
For complex data mining queries, query optimization issues arise, similar to those for the traditional database queries. However, few works have applied the cost-based query optim...
The semantic web represents meta-data as a relation of triples using the RDF data model. We have developed a virtual repository system that enables to process queries to RDF views...
Due to the flexible structures of SQL, no general approach works efficiently for all kinds of queries. Some special kinds of queries can be further optimized for better performa...