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» Query optimizer for spatial join operations
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GIS
2005
ACM
14 years 9 months ago
Two ellipse-based pruning methods for group nearest neighbor queries
Group nearest neighbor (GNN) queries are a relatively new type of operations in spatial database applications. Different from a traditional kNN query which specifies a single quer...
Hongga Li, Hua Lu, Bo Huang, Zhiyong Huang
SIGMOD
2001
ACM
136views Database» more  SIGMOD 2001»
14 years 8 months ago
Selectivity Estimation using Probabilistic Models
Estimating the result size of complex queries that involve selection on multiple attributes and the join of several relations is a difficult but fundamental task in database query...
Lise Getoor, Benjamin Taskar, Daphne Koller
GIS
1995
ACM
13 years 11 months ago
A Window Retrieval Algorithm for Spatial Databases Using Quadtrees
An algorithm is presented to answer window queries in a quadtree-based spatial database environment by retrieving the covering blocks in the underlying spatial database. It works ...
Walid G. Aref, Hanan Samet
VLDB
2001
ACM
190views Database» more  VLDB 2001»
14 years 8 days ago
LEO - DB2's LEarning Optimizer
Most modern DBMS optimizers rely upon a cost model to choose the best query execution plan (QEP) for any given query. Cost estimates are heavily dependent upon the optimizer’s e...
Michael Stillger, Guy M. Lohman, Volker Markl, Mok...
BNCOD
1997
76views Database» more  BNCOD 1997»
13 years 9 months ago
Query Evaluation in CROQUE - Calculus and Algebra Coincide
With the substantial change of declarative query languages from plain SQL to the so-called \object SQLs", in particular OQL, there has surprisingly been not much change in the...
Torsten Grust, Joachim Kröger, Dieter Gluche,...