Nyaya: Semantic data markets: a flexible environment for knowledge management - CIKM 2011 and ICDE...
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Semantic Data Markets A Flexible Environment for Knowledge Management R. De Virgilio, G. Orsi , L. Tanca and R. Torlone CIKM 2011 – Glasgow (UK)
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We present Nyaya , a flexible system for the management of Semantic-Web data which couples a general-purpose storage mechanism with efficient ontology reasoning and querying capabilities. Nyaya processes large Semantic-Web datasets, expressed in a variety of formalisms, by transforming them into a collection of Semantic Data Kiosks. Each kiosk exposes the native meta-data in a uniform fashion using Datalog± , a very general rule-based language for the representation of ontological constraints. The kiosks form a Semantic Data Market where the data in each kiosk can be uniformly accessed using conjunctive queries and where users can specify user-defined constraints over the data. Nyaya is easily extensible and robust to updates of both data and meta-data in the kiosk and can readily adapt to different logical organization of the persistent storage. The approach has been experimented using well-known benchmarks, and compared to state-of-the-art research prototypes and commercial systems.
Transcript of Nyaya: Semantic data markets: a flexible environment for knowledge management - CIKM 2011 and ICDE...
Semantic Data MarketsA Flexible Environment for Knowledge Management
R. De Virgilio, G. Orsi, L. Tanca and R. Torlone
CIKM 2011 – Glasgow (UK)
Semantic Data Management:Overview
Problem:store,query, andreason over
semantically annotated data.
Semantic Data Management:Overview
AT SCALE
Problem:store,query, andreason over
semantically annotated data.
Semantic Data Management:Overview
Common limitations:language-dependent frameworks,opaque logical and physical organization,tractable fragments are often ignored.
Semantic Data Management:Overview
Nyaya: an environment for semantic data management.uniform representation of semantic data with Datalog±, flexible and transparent storage policy,efficient reasoning and querying.
[Cali’ et Al. PODS ‘09][Cali’ et Al. VLDB ‘10]
[Atzeni et Al. VLDBJ ‘08]
[Gottlob et Al. ICDE ‘11][Orsi et Al. VLDB ‘11]
Common limitations:language-dependent frameworks,opaque logical and physical organization,tractable fragments are often ignored.
Nyaya:The kiosk
D
ΣO
ΣS
ΣO : ontological constraints
ΣS : storage constraints (mapping)
D : database
Nyaya:The kiosk
RDF
D
ΣO
ΣS
ΣO : ontological constraints
ΣS : storage constraints (mapping)
D : database
Nyaya:The kiosk
RDF
schema
data D
ΣO
ΣS
ΣO : ontological constraints
ΣS : storage constraints (mapping)
D : database
Nyaya:The kiosk
RDF
schema
data D
ΣO
ΣS
ΣO : ontological constraints
ΣS : storage constraints (mapping)
D : database
Nyaya:The kiosk
RDF
schema
data
storagemetamodel
D
ΣO
ΣS
ΣO : ontological constraints
ΣS : storage constraints (mapping)
D : database
Nyaya:The kiosk
RDF
schema
data
storagemetamodel
D
ΣO
ΣS
ΣO : ontological constraints
ΣS : storage constraints (mapping)
D : database
Nyaya:Example
database constraints
RDF
Nyaya:The semantic data market
D
ΣS
ΣO
Nyaya:The semantic data market
D
ΣS
ΣO
Nyaya:The semantic data market
D
ΣS
D
ΣS
D
ΣS
D
ΣS…
ΣO ΣO ΣO ΣO
Nyaya:The semantic data market
D
ΣS
D
ΣS
D
ΣS
D
ΣS…
ΣO ΣO ΣO ΣO
user-defined constraints
Nyaya:The semantic data market
front-endapplication
Union of Conjunctive Queries
D
ΣS
D
ΣS
D
ΣS
D
ΣS…
ΣO ΣO ΣO ΣO
user-defined constraints
Query ReformulationUse of FO-rewritability
OQ
Query ReformulationUse of FO-rewritability
QO
I phasecompilation
(ΣO)OQ
Query ReformulationUse of FO-rewritability
QO
I phasecompilation
(ΣO)
QS
II phasecompilation
(ΣS)
OQ
S
Query ReformulationUse of FO-rewritability
QO
I phasecompilation
(ΣO)
SQL translatio
n
QS
II phasecompilation
(ΣS)
OQ
S
Q*
Query ReformulationUse of FO-rewritability
QO
I phasecompilation
(ΣO)
Q* SQL translatio
n
QS
II phasecompilation
(ΣS)
evaluation
D
OQ
S
professor(X) Y teaches(X,Y)teaches(X,Y) student(Y)
q(A) teaches(A,B), student(B)Q
ΣO
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))teaches(X,Y) student(Y)ΣO
q(A) teaches(A,B), student(B)Q
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))teaches(X,Y) student(Y)ΣO
q(A) teaches(A,B), student(B)Q
p[1]
t[1]
t[2]
s[1]f
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))teaches(X,Y) student(Y)ΣO
q(A) teaches(A,B), student(B)Q
p[1]
t[1]
t[2]
s[1]f
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))teaches(X,Y) student(Y)ΣO
q(A) teaches(A,B)Q
p[1]
t[1]
t[2]
s[1]f
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))teaches(X,Y) student(Y)ΣO
q(A) teaches(A,B)Q
p[1]
t[1]
t[2]
s[1]f
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))ΣO
q(A) teaches(A,B)Q
p[1]
t[1]
t[2]
s[1]f
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))ΣO
q(A) teaches(X,Y)Q
p[1]
t[1]
t[2]
s[1]f{ XA, Bf(X) }
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))ΣO
q(A) teaches(A,B)Q
p[1]
t[1]
t[2]
s[1]f
q(A) professor(A)
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))ΣO
q(A) teaches(A,B)QΣ
p[1]
t[1]
t[2]
s[1]f
q(A) professor(A)
professor(X) i-class(Z0,X,Z1), class(Z1,’professor’)ΣSteaches(X,Y) i-objectproperty(Z0,Z1,Z2,Z3), i-class(Z1,X,Z0), i-class(Z2,Y,Z7), objectproperty(Z3,’teaches’,Z4,Z5)
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))ΣO
q(A) teaches(A,B)QΣ
p[1]
t[1]
t[2]
s[1]f
q(A) professor(A)
professor(X) i-class(Z0,X,Z1), class(Z1,’professor’)ΣS
q(A) i-objectproperty(Z0,Z1,Z2,Z3), i-class(Z1,A,Z0), i-class(Z2,B,Z7), objectproperty(Z3,’teaches’,Z4,Z5)QS
q(A) i-class(Z0,A,Z1), class(Z1,’professor’)
teaches(X,Y) i-objectproperty(Z0,Z1,Z2,Z3), i-class(Z1,X,Z0), i-class(Z2,Y,Z7), objectproperty(Z3,’teaches’,Z4,Z5)
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
professor(X) Y teaches(X,f(X))ΣO
q(A) teaches(A,B)QΣ
p[1]
t[1]
t[2]
s[1]f
q(A) professor(A)
professor(X) i-class(Z0,X,Z1), class(Z1,’professor’)ΣS
q(A) i-objectproperty(Z0,Z1,Z2,#(teaches)), i-class(Z1,A,Z0)QSq(A) i-class(Z0,A,#(professor))
teaches(X,Y) i-objectproperty(Z0,Z1,Z2,Z3), i-class(Z1,X,Z0), i-class(Z2,Y,Z7), objectproperty(Z3,’teaches’,Z4,Z5)
Query ReformulationExample [Gottlob, Orsi and Pieris ICDE ‘11]
ExperimentsQuerying
UOBM Tbox (Approximated)Instance of 12.8 million triples
ExperimentsQuerying
UOBM Tbox (Approximated)Instance of 12.8 million triples
ExperimentsLoading and Updates
ExperimentsLoading and Updates
If the language of ΣO is FO-rewritable
fact updates reduce to updates in a DBMSpredicate updates reduce to re-compute the rewriting
ConclusionWhat should we do?
Identifying tractable classes of ontological constraints is crucialcurrent commercial systems do not do that
Intensional query reformulation delivers very good query performance
Ontology-based data access (ODBA) seamlessly extends traditional database technology
This is the endThank you
The Nyaya Family
http://mais.dia.uniroma3.it/Nyaya
