62 search results - page 3 / 13 » Containment of Conjunctive Queries over Databases with Null ... |
EDBT
2002
ACM
14 years 5 months ago
2002
ACM
The problem of finding contained rewritings of queries using views is of great importance in mediated data integration systems. In this paper, we first present a general approach f...
EDBT
2004
ACM
14 years 5 months ago
2004
ACM
We study the problem of answering queries over sources with limited access patterns. The problem is to decide whether a given query Q is feasible, i.e., equivalent to an executable...
ALT
2000
Springer
13 years 9 months ago
2000
Springer
A conjunctive query problem in relational database theory is a problem to determine whether or not a tuple belongs to the answer of a conjunctive query over a database. Here, a tup...
ICDE
2007
IEEE
14 years 6 months ago
2007
IEEE
Incompleteness due to missing attribute values (aka "null values") is very common in autonomous web databases, on which user accesses are usually supported through media...
VLDB
2007
ACM
14 years 5 months ago
2007
ACM
Incompleteness due to missing attribute values (aka "null values") is very common in autonomous web databases, on which user accesses are usually supported through media...