320 search results - page 20 / 64 » A Theory of Spatio-Temporal Database Queries |
PODS
2009
ACM
14 years 8 months ago
2009
ACM
We consider the problem of deciding query equivalence for a conjunctive language in which queries output complex objects composed from a mixture of nested, unordered collection ty...
ICDT
2010
ACM
13 years 9 months ago
2010
ACM
When a query is evaluated under bag semantics, each answer is returned as many times as it has derivations. Bag semantics has long been recognized as important, especially when ag...
PODS
2000
ACM
13 years 12 months ago
2000
ACM
We consider spatial databases in the plane that can be defined by polynomial constraint formulas. Motivated by applications in geographic information systems, we investigate line...
PODS
2010
ACM
14 years 19 days ago
2010
ACM
We investigate a higher-order query language that embeds operators of the positive relational algebra within the simply-typed λ-calculus. Our language allows one to succinctly de...
PODS
1997
ACM
13 years 11 months ago
1997
ACM
We rework parts of the classical relational theory when the underlying domain is a structure with some interpreted operations that can be used in queries. We identify parts of the...