Estimating the selectivity of a query is a key step in almost any cost-based query optimizer.
Most of today's databases rely on histograms or samples that are periodically refreshed by …

Despite a large body of work on xml query processing in relational environment, systematic
study of not-twig queries has received little attention in the literature. Such queries contain …

Despite a large body of work on XPath query processing in relational environment,
systematic study of queries containing not-predicates have received little attention in the …

XML query languages use directional path expressions to locate data in an XML data
collection. They are tightly coupled to the structure of a data collection, and can fail when …

With the rapid emergence of xml as the de facto standard for exchanging data on the Web,
the interest in efficiently querying xml data sources using mature relational technology has …

We tackle the problem of obtaining statistics on content and structure of XML documents by
using summaries which may provide cardinality estimations for XML query expressions. Our …

We tackle the problem of obtaining statistics on content and structure of XML documents by
using summaries which may provide cardinality estimations for XML query expressions. Our …

Despite a large body of work on xml twig query processing in relational environment,
systematic study of xml join evaluation has received little attention in the literature. In this …

Despite a large body of work on XML twig query processing in relational environment,
systematic study of XML join evaluation has received little attention in the literature. In this …

The automated optimization of declarative user queries is a classical hallmark of database
technology. XML, with its support for deep data hierarchies and powerful query operators …