uk.ac.ic.doc.rodex.qproc
Class RangeBasedQueryRewriter

java.lang.Object
  uk.ac.ic.doc.rodex.qproc.QueryRewriter
      uk.ac.ic.doc.rodex.qproc.RangeBasedQueryRewriter

public class RangeBasedQueryRewriter
extends QueryRewriter

Field Summary

Fields inherited from class uk.ac.ic.doc.rodex.qproc.QueryRewriter

query, views

Constructor Summary

RangeBasedQueryRewriter(ASG query, ASG extent)
Creates a new instance of RangeBasedQueryRewriter given only a list of cached views

RangeBasedQueryRewriter(QueryAnalyser qa, ASG extent)
Creates a new instance of RangeBasedQueryRewriter given only a list of cached views

Method Summary

QueryAnalyser	analyse() Implements method in QueryWriter parent class Analyse query and view rules into head vars and sub-goals in order to prepare for the actual rewrite to take place
QueryAnalyser	getQueryAnalyser() Return query analyser
AutoMedType[]	getValueRange(QuerySubGoal qsg) Get a value range for a query sub-goal in the query based on the functions associated to this sub-goal.
AutoMedType[]	getValueRange(QueryVariable var) Get a value range for query variable in the query based on the functions associated to this variable.
QueryRewriterResult	rewrite() Rewrite an existing query into a set of equivalent sub-queries based on range analysis.

Methods inherited from class uk.ac.ic.doc.rodex.qproc.QueryRewriter

getQueryRewriterInstance, getQueryRewriterInstance, getQueryRewriterInstance, getQueryRewriterInstance

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RangeBasedQueryRewriter

public RangeBasedQueryRewriter(ASG query,
                               ASG extent)

Creates a new instance of RangeBasedQueryRewriter given only a list of cached views

RangeBasedQueryRewriter

public RangeBasedQueryRewriter(QueryAnalyser qa,
                               ASG extent)

Creates a new instance of RangeBasedQueryRewriter given only a list of cached views

Method Detail

analyse

public QueryAnalyser analyse()
                      throws QueryRewriterException,
                             QueryIntegrityException

Implements method in QueryWriter parent class
Analyse query and view rules into head vars and sub-goals in order to prepare
for the actual rewrite to take place

Specified by:

analyse in class QueryRewriter

Returns:

QueryAnalysre object that contains query's metadata

Throws:

QueryRewriterException

QueryIntegrityException

getQueryAnalyser

public QueryAnalyser getQueryAnalyser()

Return query analyser

Specified by:

getQueryAnalyser in class QueryRewriter

rewrite

public QueryRewriterResult rewrite()
                            throws QueryRewriterException

Rewrite an existing query into a set of equivalent sub-queries based on range analysis. Range-based analysis is performed for both numeric and string data values.

Specified by:

rewrite in class QueryRewriter

Throws:

QueryRewriterException

getValueRange

public AutoMedType[] getValueRange(QuerySubGoal qsg)

Get a value range for a query sub-goal in the query based on the functions associated to this sub-goal.
This method supports two types of query expressions: numeric and literal

Parameters:

var - a QueryVariable object to analyse

Returns:

AutoMedType[] an array of two AutoMedType objects, one for the lower bound and the other for the upper bound

getValueRange

public AutoMedType[] getValueRange(QueryVariable var)

Get a value range for query variable in the query based on the functions associated to this variable.
This method supports two types of query expressions: numeric and literal

Parameters:

var - a QueryVariable object to analyse

Returns:

AutoMedType[] an array of two AutoMedType objects, one for the lower bound and the other for the upper bound