8763 search results - page 293 / 1753 » Querying Database Knowledge |
166
click to vote
PODS
2007
ACM
16 years 6 months ago
2007
ACM
Variables are the distinguishing new feature of XPath 2.0 which permits to select n-tuples of nodes in trees. It is known that the Core of XPath 2.0 captures n-ary first-order (FO...
165
click to vote
VLDB
2004
ACM
16 years 18 hour ago
2004
ACM
PIVOT and UNPIVOT, two operators on tabular data that exchange rows and columns, enable data transformations useful in data modeling, data analysis, and data presentation. They ca...
309
click to vote
ICDE
2009
IEEE
16 years 8 months ago
2009
IEEE
Abstract-- In sensor environments and moving robot applications, the position of an object is often known imprecisely because of measurement error and/or movement of the object. In...
201
click to vote
DLOG
2011
14 years 10 months ago
2011
We show that, although conjunctive queries over OWL 2 QL ontologies are reducible to database queries, no algorithm can construct such a reduction in polynomial time without changi...
193
Voted
SIGMOD
2010
ACM
15 years 11 months ago
2010
ACM
Many web queries seek information about named entities (such as products or people). Web search engines federate such entity-oriented queries to relevant structured databases; the...