operation
subset
subset of operations
chapter
false
correctness
1993-01-01
en
graph-based data model
data access paradigm
query optimizer
access plan results
query optimization
scans
calculus
algebraic expressions
low-level evaluation strategies
cut
language
2022-01-01T19:17
paradigm
user level queries
A logic for rule-based query optimization in graph-based data models
1993
semantics
strategies
properties
queries
We present a wide-spectrum algebra and refinement calculus designed to allow one to reason about query optimization in graph-based data models.A query language is wide-spectrum if it can be used to express both user level queries as well as low-level evaluation strategies or access plans. This property enables rule-based query optimization to be viewed as the process of refining expressions in such a language: “non-procedural” sub-expressions are gradually replaced by more “procedural” sub-expressions until an unambiguous access plan results. We begin by presenting an algebra that is wide-spectrum in this sense. One subset of operations within the algebra can be used to define the formal semantics of a non-procedural query language for graph-based data models. Another subset can express common data access paradigms such as an index scan, the “cut” operator in Prolog or the nested-iteration join processing strategy.We then present a refinement calculus over the algebra which defines when one algebraic expression subsumes another. The calculus makes it possible to formally prove the correctness of rewrite rules used in rule-based query optimizers, and is sufficiently expressive to admit rules encoding many forms of semantic query optimization.
query language
evaluation strategies
plan results
processing strategies
nested-iteration join processing strategy
https://scigraph.springernature.com/explorer/license/
level queries
expression
Prolog
operators
wide-spectrum algebra
optimizer
refining expressions
model
access plan
formal semantics
form
non-procedural query languages
common data access paradigms
data model
plan
rule-based query optimization
https://doi.org/10.1007/3-540-57530-8_8
access paradigm
algebra
semantic query optimization
refinement calculus
index scan
process
120-145
rule-based query optimizer
results
reasons
logic
unambiguous access plan results
rules
join processing strategy
rewrite rules
optimization
sense
chapters
Tsur
Shalom
Deductive and Object-Oriented Databases
978-3-540-57530-6
978-3-540-48212-3
Neil
Coburn
Springer Nature
Information and Computing Sciences
Ceri
Stefano
Information Systems
dimensions_id
pub.1052689766
Tanaka
Katsumi
Grant E.
Weddell
Springer Nature - SN SciGraph project
10.1007/3-540-57530-8_8
doi
Department of Computer Science, University of Waterloo, UK
Department of Computer Science, University of Waterloo, UK