121 search results - page 19 / 25 » On Containment of Conjunctive Queries with Negation |
EDBT
2006
ACM
14 years 7 months ago
2006
ACM
The problem of rewriting queries using views has received significant attention because of its applications in a wide variety of datamanagement problems. For select-project-join SQ...
SIGMOD
2004
ACM
14 years 7 months ago
2004
ACM
The prevalent use of XML highlights the need for a generic, flexible access-control mechanism for XML documents that supports efficient and secure query access, without revealing ...
VLDB
2011
ACM
13 years 2 months ago
2011
ACM
Schema mappings are high-level specifications that describe the relationship between two database schemas. They are an important tool in several areas of database research, notab...
ICDT
2003
ACM
14 years 28 days ago
2003
ACM
Abstract. Repairing a database means bringing the database in accordance with a given set of integrity constraints by applying modifications that are as small as possible. In the ...
ICDE
2012
IEEE
11 years 10 months ago
2012
IEEE
— Uncertainties in data arise for a number of reasons: when the data set is incomplete, contains conflicting information or has been deliberately perturbed or coarsened to remov...