Download s1354-fuxman

ConQuer: Efficient Management
of Inconsistent Databases
Presented by:
Ariel Fuxman (Univ. of Toronto)
Joint work with:
Diego Fuxman (Univ. Nacional del Sur)
Renée J. Miller (Univ. of Toronto)
ConQuer
 A system designed to answer SQL
queries over inconsistent databases
Name
Income
Peter
40K
INCONSISTENT
Paul
400K DATABASE
Peter
200K
Mary
110K
Mary
130K
name should be the key
Ariel Fuxman, Diego Fuxman, Renée J. Miller
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One Application
Customer Relationship Management (CRM)
Sales
Shipping
Customer Support
Web Forms
Integrated
Customer
Database
Demographic Data
Ariel Fuxman, Diego Fuxman, Renée J. Miller
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Disagreement Between Sources
 Which tuple for Peter should we delete?
• Removing both tuples loses consistent information
• Deciding the correct income may require human intervention
name
address
…
income
Peter
276 College Street
….
40K
Paul
100 Bloor Street
…
400K
Mary
20 Union Street
…
110K
name
address
…
income
Peter
276 College Street
….
200K
Paul
100 Bloor Street
…
400K
Mary
20 Union Street
…
130K
Ariel Fuxman, Diego Fuxman, Renée J. Miller
sales
web
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Inconsistent Integrated Database
Transfer all conflicting tuples to the integrated database
Sales
name
…
income
Peter
…
40K
Paul
…
400K
name
…
income
Mary
…
110K
Peter
…
40K
Integrated Database
Peter
…
200K
INCONSISTENT
Paul
Web
name
…
income
Mary
Peter
…
200K
Mary
Paul
…
400K
Mary
…
130K
Ariel Fuxman, Diego Fuxman, Renée J. Miller
…
400K
DATABASE
…
110K
…
130K
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Query Answering
Offering a Platinum credit card…
q=“Get customers who make more than 100K”
Peter,Paul,Mary
Peter should NOT be offered a Platinum card!!
name
income
Peter
40K
sales
Peter
200K
web
Paul
400K
sales/web
Mary
110K
sales
Mary
130K
web
Ariel Fuxman, Diego Fuxman, Renée J. Miller
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Semantics of Query Answering
 Get customers who possibly make more than 100K
 Get customers who certainly make more than 100K
CONSISTENT ANSWER
[Arenas, Bertossi, Chomicki 99]
 There is considerable work in the literature
about theoretical aspects of consistent answers
 ConQuer: Efficient computation of consistent
answers
Ariel Fuxman, Diego Fuxman, Renée J. Miller
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Query Answering in ConQuer
Query q
Keys
Consistent
May not get consistent
answer
to q
answers
ConQuer’s
Rewriting
Algorithm
[ICDT 05]
[SIGMOD 05]
Commercial database
engine
Rewritten
Q*
Ariel Fuxman, Diego Fuxman, Renée J. Miller
Inconsistent
database
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Demo
 Present a case study of an inconsistent
database about airports and cities
 Explain the automatically generated
rewritings
 Deal with Select-Project-Join queries with
grouping and aggregation
Ariel Fuxman, Diego Fuxman, Renée J. Miller
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ConQuer papers
 A. Fuxman, E. Fazli, and R. J. Miller.
ConQuer: Efficient Management of
Inconsistent Databases, SIGMOD 2005.
 A. Fuxman and R. J. Miller. First-Order
Query Rewriting for Inconsistent
Databases, ICDT 2005.
Ariel Fuxman, Diego Fuxman, Renée J. Miller
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Schema
AIRPORTS
A_ICAO
a_name
a_city
a_country
CODES
a_latdeg
C_IATA
a_latmin
c_icao
a_latsec
CITIES
CI_NAME
CI_COUNTRY
ci_population
ci_year
a_latdir
a_height
Ariel Fuxman, Diego Fuxman, Renée J. Miller
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