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Tema 1 Applicazioni per basi di dati su
Internet e Intranet
Use of ontologies and extensional inter-schema
properties for integration
Rapporto D1.R2
30 Aprile 2001
D. Beneventano, S. Bergamaschi, F. Guerra, S.
Castano, M. Vincini
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Abstract
We detail and extend the method described in
D1.R1

• we take into account the extensional intra and
  inter-schema properties
• we show as these properties influence the
  integration process
• complete syntax and semantics of the OCDL
  Description Logic
• theoretical foundations of the techniques to
  discover affinity

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Extensional relationships in ODLI3

• ltC1 SYNext C2gt the instances of C1 are the
  same of C2
• ltC1 NText C2gt the instances C1 are a subset of
  the instances of C2

extensional relationships constrain the structure
of the two classes C1 NText C2 is equivalent to
an ISA relationship.
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Common Thesaurus
schema-derived extensional relationships

• ISA relationship in object source schemas
• foreign keys in relational source schemas

interface Restaurant ( FD source key r_code
... interface Bistro
(FD source key r_code
foreign_key(r_code) references Restaurant, ...
lt Bistro NText Restaurant gt
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Common Thesaurus
inferred extensional relationships
lt FD.Bistro NText FD.Restaurant gt rule Rule2
forall X in FD.Restaurant (X.pers_id in
FD.Person) then X in ED.Fast-Food interface
Bistro (FD source foreign_key(pers_id)
references Person
lt FD.Bistro Ntext ED.Fast-Food gt
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Clustering

• extensional relationshipd force the inclusion
  of a class in a cluster.

classes that have an extensional relationship
with at least one class in the cluster and not
yet included in i), are forced to belong to the
cluster anyway,
the integrated global class is representative of
all possible semantically related source
classes.
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Phase 2
Exploiting extensional knowledge in query
processing activities D1.R8 Functional
specification of the Query Manager (MO)

• optimal query reformulation, by detecting
  extensionally overlapping classes
• object fusion (to identify instances of the same
  object and fuse them)
• by defining join criteria among classes