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AGGREGATE PATH INDEX FOR INCREMENTL WEB VIEW MAINTENANCE
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AGGREGATE PATH INDEX FOR INCREMENTL WEB VIEW MAINTENANCE. Author: ... Worcester Polytechnic Institure. Presented by Pengpeng Lu. OUTLINE. OBJECTIVE. INTRODUCTION ... – PowerPoint PPT presentation
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Title: AGGREGATE PATH INDEX FOR INCREMENTL WEB VIEW MAINTENANCE
1
AGGREGATE PATH INDEX FOR INCREMENTL WEB VIEW
MAINTENANCE
- Author Li Chen and Elke Rundensteiner
- Department of Computer Science
- Worcester Polytechnic Institure
- Presented by Pengpeng Lu
2
OUTLINE
- OBJECTIVE
- INTRODUCTION
- MAINTENANCE STRATEGY
- MAINTENANCE APPROACH
- EVALUATION
- CONCLUSION
3
OBJECTIVE
- DEVELOP EFFICIENT WEB VIEW MAINTENANCE TECHNIQUE
Web
Web1
Web2
Web3
Web7
Web6
Web4
Web5
4
INTRODUCTION
- WEB DATA
- DYNAMIC
- NO STRICT SCHEMA FOR XML FILE
- WEB DATA NOT EASY TO BE SEPARATED
- WEB VIEW MAINTENANCE APPROACHES
- RE-COMPUTE FROM SCRATCH---NOT EFFICIENT
- INCREMENTAL MAINTENANCE---EFFIEIENT
- AGGREGATE PATH INDEX (APIX)
5
MAINTENANCE STRATEGY
- DOM TREE STRUCTURE (XML DOCUMENT)
6
MAINTENANCE STRATEGY
- WEB VIEW SPECIFICATION (XQL)
- Define web view favorite_entries as
- /E-mail/shop/_at_categorytoy/entry_at_makerASE
and - _at_quantitygt0 and price lt20 and itembook
QUERY TREE
APIX INDEX
E
S
/E-mail/shop/_at_categorytoy/entry_at_makerASE
and _at_quantitygt0 and price lt20 and itembook
e
m
q
p
i
7
MAINTENANCE APPROACH
- PATH PATTERN EVALUATION
- TWO-STEP
- PATH PATTERN
- EVALUATION
- Store qualified
- objects into APIX
- PREDICATE VALUE
- EVALUATION
/E-mail/shop/_at_categorytoy/entry_at_makerASE
and _at_quantitygt0 and price lt20 and itembook
8
MAINTENANCE APPROACH
- PREDICATE VALUE EVALUATION
- View Object
- Path Pattern Satisfiable
- ER Value is True
- Data Update Operations
- Insertion
- Deletion
- Change
Evaluation Vaue (ER) True/1
False/0
9
MAINTENANCE APPROACH
- CHECK IRRELEVANT CASES
- Query Irrelevant Update
- Value Irrelevant Change
- Irrelevant Deletion
- Example ltIns, 5, entry, 15gt
RELEVANT CASES Example ltIns, 11, item,
36gt
10
COST ANALYSIS
ltIns, 15, item, 39gt
CostnaiveCE CsCcCe CmCqCpCi CostAPIX1(C
mCqCpCi) /24-1
11
ADVANTAGE
- Prune the traversal space---reduce the
accesses to base data - Cache a reduced set of relevant objects---save
index space
DISADVANTAGE
APIX index table cost extra space for the columns
12
CONCLUSION
- APIX STRUCTURE WAS PROPOSED FOR
- INCREMENTAL WEB VIEW MAINTENANCE
- THROUGH COST ANALYSIS, APIX FOR WEB
- VIEW MAINTENANCE DEMONSTRATED
- ENHANCED EFFICIENCY
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