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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
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OUTLINE OBJECTIVE INTRODUCTION MAINTENANCE STRATEGY MAINTENANCE APPROACH EVALUATION CONCLUSION
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OBJECTIVE DEVELOP EFFICIENT WEB VIEW MAINTENANCE TECHNIQUE Web Web1Web2 Web3 Web4Web5 Web7Web6
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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)
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MAINTENANCE STRATEGY DOM TREE STRUCTURE (XML DOCUMENT)
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MAINTENANCE STRATEGY WEB VIEW SPECIFICATION (XQL) Define web view favorite_entries as /E-mail/shop/[@category=“toy”]/entry[@maker=“ASE” and @quantity>0 and price <$20 and item=“book”] /E-mail/shop/[@category=“toy”]/entry[@maker=“ASE” and @quantity>0 and price <$20 and item=“book”] E S emq p i QUERY TREE APIX INDEX: I (v) v1v1 v2v2 v3v3 V 4…
![MAINTENANCE STRATEGY WEB VIEW SPECIFICATION (XQL) Define web view favorite_entries as toy ASE and price <$20 and item= book ] toy ASE and price <$20 and item= book ] E S emq p i QUERY TREE APIX INDEX: I (v) v1v1 v2v2 v3v3 V 4…](http://images.slideplayer.com/17/5350723/slides/slide_6.jpg "MAINTENANCE STRATEGY WEB VIEW SPECIFICATION (XQL) Define web view favorite_entries as toy ASE and price <$20 and item= book ] toy ASE and price <$20 and item= book ] E S emq p i QUERY TREE APIX INDEX: I (v) v1v1 v2v2 v3v3 V 4…")
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MAINTENANCE APPROACH TWO-STEP: PATH PATTERN EVALUATION Store “qualified” objects into APIX PREDICATE VALUE EVALUATION PATH PATTERN EVALUATION /E-mail/shop/[@category=“toy”]/entry[@maker=“ASE” and @quantity>0 and price <$20 and item=“book”]
![MAINTENANCE APPROACH TWO-STEP: PATH PATTERN EVALUATION Store qualified objects into APIX PREDICATE VALUE EVALUATION PATH PATTERN EVALUATION toy ASE and price <$20 and item= book ]](http://images.slideplayer.com/17/5350723/slides/slide_7.jpg "MAINTENANCE APPROACH TWO-STEP: PATH PATTERN EVALUATION Store qualified objects into APIX PREDICATE VALUE EVALUATION PATH PATTERN EVALUATION toy ASE and price <$20 and item= book ]")
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MAINTENANCE APPROACH PREDICATE VALUE EVALUATION Evaluation Vaue (ER): True/1 False/0 View Object: 1.Path Pattern Satisfiable 2.ER Value is True Data Update Operations: Insertion Deletion Change
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MAINTENANCE APPROACH CHECK IRRELEVANT CASES: Query Irrelevant Update Value Irrelevant Change Irrelevant Deletion Example: RELEVANT CASES: Example:
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COST ANALYSIS Cost naive =C E +C s +C c +C e + C m +C q +C p +C i Cost APIX =1+(C’ m +C’ q +C’ p +C’ i ) /2 4 -1
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ADVANTAGE DISADVANTAGE Prune the traversal space---reduce the accesses to base data Cache a reduced set of relevant objects---save index space APIX index table cost extra space for the columns
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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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