The document describes an ontology-based data access (OBDA) approach that allows users to query relational databases through an ontology and semantic mappings. It presents the components of an OBDA system, including relational databases, a user ontology, semantic mappings between the ontology and databases, an OBDA-enabled reasoner, and communication facilities between components. An example scenario involving a financial services ontology and corresponding database schemas is also provided.

1. Realizing Ontology
Based Data Access
A Plugin for Protégé
Mariano Rodríguez-Muro
Lina Lubyte
Diego Calvanese
Free University of Bozen Bolzano
Knowledge Representation meets Databases group
Bolzano, Italy
Thursday, August 8, 13

2. Ontologies
Thursday, August 8, 13

3. Ontologies
• What are Ontologies?
• Shared conceptualizations of a domain of
discourse
Thursday, August 8, 13

4. Ontologies
• What are Ontologies?
• Shared conceptualizations of a domain of
discourse
• Formal Semantics
Thursday, August 8, 13

5. Ontologies
• What are Ontologies?
• Shared conceptualizations of a domain of
discourse
• Formal Semantics
• Allow us to perform complex inferencing
Thursday, August 8, 13

6. Ontologies
• What are Ontologies?
• Shared conceptualizations of a domain of
discourse
• Formal Semantics
• Allow us to perform complex inferencing
• Description Logics!!
Thursday, August 8, 13

7. Reasoners
Thursday, August 8, 13

8. Reasoners
• Software systems that allow us to perform
inferences over ontologies
Thursday, August 8, 13

9. Reasoners
• Software systems that allow us to perform
inferences over ontologies
• Examples of reasoning services in DL
reasoners:
• Subsumption checking, Instance checking,
consistency checking
Thursday, August 8, 13

10. Wouldn’t it be nice if...
Data Source
Data Source
Data Source
Data Layer
User Ontology
Semantic LayerUser
Queries
Semantic
Mappings
Thursday, August 8, 13

11. Wouldn’t it be nice if...
Data Source
Data Source
Data Source
Data Layer
User Ontology
Semantic LayerUser
Queries
Semantic
Mappings
Data Source
Data Source
Data Source
Data Layer
User Ontology
Semantic LayerUser
Queries
Semantic
Mappings
Thursday, August 8, 13

12. Wouldn’t it be nice if...
RDBMs
Semantic Layer Data Layer
User
Queries
Ontology RDBMs
Data Layer
Semantic
Mappings
OBDA-Enabled Reasoner
RDBMs
Semantic Layer Data Layer
User
Queries
Ontology RDBMs
Data Layer
Semantic
Mappings
OBDA-Enabled Reasoner
Thursday, August 8, 13

13. Wouldn’t it be nice if...
Meet OBDA
RDBMs
Semantic Layer Data Layer
User
Queries
Ontology RDBMs
Data Layer
Semantic
Mappings
OBDA-Enabled Reasoner
RDBMs
Semantic Layer Data Layer
User
Queries
Ontology RDBMs
Data Layer
Semantic
Mappings
OBDA-Enabled Reasoner
Thursday, August 8, 13

14. Example
Scenario:Software consultant for financial
institutions.
Objective: Achieve better reusability and
modularization of their software solutions.
Preconditions: Requirements are fixed
requirements that the users must meet.
Thursday, August 8, 13

15. Thursday, August 8, 13

16. StockBroker
Trader
StockExchangeMember
Investor
Dealer StockTrader
tradesOnBehalfOf
usesBroker
Person
1 .. *
<<ident>>financialInstrumentID: int
FinancialInstrument
<<ident>listdate: date
StockExchangeList
<<ident>transactionID:int
transactionDate: Date
Transaction
amountOfShares: int
typeOfShares: Boolean
Stock 1 .. *0 .. *
listsStock
StockExchangeMember
isExecutedBy
1 .. 1
Company
involvesInstrument
isTradedIn
1 .. 1
0 .. 1
Acquisition Offer
isListedIn
1 .. 1 0 .. *
hasStock
belongsToCompany
{disjoint}
Investor
isExecutedFor1 .. 1
companyName: String
marketShares: Integer
netWorth: Real
Company
firstName: Name
lastName: String
dateOfBirth: Date
ssn: String
PhysicalPersonLegalPerson
<<ident>personID: int
Person
<<ident>addressID: int
inStreet: Sring
hasNumber: Int
inCity: String
inState: String
inCountry: String
Address
1 .. *
1 .. 1
hasAddress{disjoint}
Thursday, August 8, 13

17. StockBroker
Trader
StockExchangeMember
Investor
Dealer StockTrader
tradesOnBehalfOf
usesBroker
Person
1 .. *
<<ident>>financialInstrumentID: int
FinancialInstrument
<<ident>listdate: date
StockExchangeList
<<ident>transactionID:int
transactionDate: Date
Transaction
amountOfShares: int
typeOfShares: Boolean
Stock 1 .. *0 .. *
listsStock
StockExchangeMember
isExecutedBy
1 .. 1
Company
involvesInstrument
isTradedIn
1 .. 1
0 .. 1
Acquisition Offer
isListedIn
1 .. 1 0 .. *
hasStock
belongsToCompany
{disjoint}
Investor
isExecutedFor1 .. 1
companyName: String
marketShares: Integer
netWorth: Real
Company
firstName: Name
lastName: String
dateOfBirth: Date
ssn: String
PhysicalPersonLegalPerson
<<ident>personID: int
Person
<<ident>addressID: int
inStreet: Sring
hasNumber: Int
inCity: String
inState: String
inCountry: String
Address
1 .. *
1 .. 1
hasAddress{disjoint}
MiFID
Thursday, August 8, 13

18. StockBroker
Trader
StockExchangeMember
Investor
Dealer StockTrader
tradesOnBehalfOf
usesBroker
Person
1 .. *
<<ident>>financialInstrumentID: int
FinancialInstrument
<<ident>listdate: date
StockExchangeList
<<ident>transactionID:int
transactionDate: Date
Transaction
amountOfShares: int
typeOfShares: Boolean
Stock 1 .. *0 .. *
listsStock
StockExchangeMember
isExecutedBy
1 .. 1
Company
involvesInstrument
isTradedIn
1 .. 1
0 .. 1
Acquisition Offer
isListedIn
1 .. 1 0 .. *
hasStock
belongsToCompany
{disjoint}
Investor
isExecutedFor1 .. 1
companyName: String
marketShares: Integer
netWorth: Real
Company
firstName: Name
lastName: String
dateOfBirth: Date
ssn: String
PhysicalPersonLegalPerson
<<ident>personID: int
Person
<<ident>addressID: int
inStreet: Sring
hasNumber: Int
inCity: String
inState: String
inCountry: String
Address
1 .. *
1 .. 1
hasAddress{disjoint}
MiFID
Applications
Thursday, August 8, 13

19. StockBroker
Trader
StockExchangeMember
Investor
Dealer StockTrader
tradesOnBehalfOf
usesBroker
Person
1 .. *
<<ident>>financialInstrumentID: int
FinancialInstrument
<<ident>listdate: date
StockExchangeList
<<ident>transactionID:int
transactionDate: Date
Transaction
amountOfShares: int
typeOfShares: Boolean
Stock 1 .. *0 .. *
listsStock
StockExchangeMember
isExecutedBy
1 .. 1
Company
involvesInstrument
isTradedIn
1 .. 1
0 .. 1
Acquisition Offer
isListedIn
1 .. 1 0 .. *
hasStock
belongsToCompany
{disjoint}
Investor
isExecutedFor1 .. 1
companyName: String
marketShares: Integer
netWorth: Real
Company
firstName: Name
lastName: String
dateOfBirth: Date
ssn: String
PhysicalPersonLegalPerson
<<ident>personID: int
Person
<<ident>addressID: int
inStreet: Sring
hasNumber: Int
inCity: String
inState: String
inCountry: String
Address
1 .. *
1 .. 1
hasAddress{disjoint}
Client
addressid
......
dateofbirth ssnid
...
lastname
...... ...
name
Broker
addressid
...... ...
name ssn
......
id
...
lastname dateofbirth
BrokerWorksFor
...... ...
brokerid companyid clientid
Company
...
addressid
...
id
...
name
...
networthmarketshares
...
Transaction
......
id
...... ...
brokerid forclientidtype forcompanyiddate stockid
... ...
StockBookList
date
...
stockid
...
Address
country
...
state
......
id
...
street
...
citynumber
...
StockInformation
...
companyid
...
sharetypeid
...
numberofshares
...
MiFIDNew Client
Applications
Thursday, August 8, 13

20. StockBroker
Trader
StockExchangeMember
Investor
Dealer StockTrader
tradesOnBehalfOf
usesBroker
Person
1 .. *
<<ident>>financialInstrumentID: int
FinancialInstrument
<<ident>listdate: date
StockExchangeList
<<ident>transactionID:int
transactionDate: Date
Transaction
amountOfShares: int
typeOfShares: Boolean
Stock 1 .. *0 .. *
listsStock
StockExchangeMember
isExecutedBy
1 .. 1
Company
involvesInstrument
isTradedIn
1 .. 1
0 .. 1
Acquisition Offer
isListedIn
1 .. 1 0 .. *
hasStock
belongsToCompany
{disjoint}
Investor
isExecutedFor1 .. 1
companyName: String
marketShares: Integer
netWorth: Real
Company
firstName: Name
lastName: String
dateOfBirth: Date
ssn: String
PhysicalPersonLegalPerson
<<ident>personID: int
Person
<<ident>addressID: int
inStreet: Sring
hasNumber: Int
inCity: String
inState: String
inCountry: String
Address
1 .. *
1 .. 1
hasAddress{disjoint}
Client
addressid
......
dateofbirth ssnid
...
lastname
...... ...
name
Broker
addressid
...... ...
name ssn
......
id
...
lastname dateofbirth
BrokerWorksFor
...... ...
brokerid companyid clientid
Company
...
addressid
...
id
...
name
...
networthmarketshares
...
Transaction
......
id
...... ...
brokerid forclientidtype forcompanyiddate stockid
... ...
StockBookList
date
...
stockid
...
Address
country
...
state
......
id
...
street
...
citynumber
...
StockInformation
...
companyid
...
sharetypeid
...
numberofshares
...
Applications
MiFIDNew Client
Thursday, August 8, 13

21. StockBroker
Trader
StockExchangeMember
Investor
Dealer StockTrader
tradesOnBehalfOf
usesBroker
Person
1 .. *
<<ident>>financialInstrumentID: int
FinancialInstrument
<<ident>listdate: date
StockExchangeList
<<ident>transactionID:int
transactionDate: Date
Transaction
amountOfShares: int
typeOfShares: Boolean
Stock 1 .. *0 .. *
listsStock
StockExchangeMember
isExecutedBy
1 .. 1
Company
involvesInstrument
isTradedIn
1 .. 1
0 .. 1
Acquisition Offer
isListedIn
1 .. 1 0 .. *
hasStock
belongsToCompany
{disjoint}
Investor
isExecutedFor1 .. 1
companyName: String
marketShares: Integer
netWorth: Real
Company
firstName: Name
lastName: String
dateOfBirth: Date
ssn: String
PhysicalPersonLegalPerson
<<ident>personID: int
Person
<<ident>addressID: int
inStreet: Sring
hasNumber: Int
inCity: String
inState: String
inCountry: String
Address
1 .. *
1 .. 1
hasAddress{disjoint}
Client
addressid
......
dateofbirth ssnid
...
lastname
...... ...
name
Broker
addressid
...... ...
name ssn
......
id
...
lastname dateofbirth
BrokerWorksFor
...... ...
brokerid companyid clientid
Company
...
addressid
...
id
...
name
...
networthmarketshares
...
Transaction
......
id
...... ...
brokerid forclientidtype forcompanyiddate stockid
... ...
StockBookList
date
...
stockid
...
Address
country
...
state
......
id
...
street
...
citynumber
...
StockInformation
...
companyid
...
sharetypeid
...
numberofshares
...
Semantic
Mapping!
Applications
MiFIDNew Client
Thursday, August 8, 13

22. Components revised
RDBMs
Semantic Layer Data Layer
User
Queries
Ontology RDBMs
Data Layer
Semantic
Mappings
OBDA-Enabled Reasoner
Thursday, August 8, 13

23. Components revised
RDBMs
Semantic Layer Data Layer
User
Queries
Ontology RDBMs
Data Layer
Semantic
Mappings
OBDA-Enabled Reasoner
Communication
Facilities
Thursday, August 8, 13

24. Components revised
RDBMs
Semantic Layer Data Layer
User
Queries
Ontology RDBMs
Data Layer
Semantic
Mappings
OBDA-Enabled Reasoner
Communication
Facilities
Reasoners need to
be extended with
new paradigm
Thursday, August 8, 13

25. Components revised
RDBMs
Semantic Layer Data Layer
User
Queries
Ontology RDBMs
Data Layer
Semantic
Mappings
OBDA-Enabled Reasoner
Communication
Facilities
Reasoners need to
be extended with
new paradigm
Design Tools!
Thursday, August 8, 13

26. First steps
Protégé
Protégé
OWLPlugin
OBDA
Plugin
SERVERSIDECLIENTSIDE
DIG 1.2 + OBDA
Extension
TBox
DS Info +
Mappings
QuOnto
DIG Server for
QuOnto
DS Info +
Mappings
TBox
RDBMS
Thursday, August 8, 13

27. First steps
Protégé
Protégé
OWLPlugin
OBDA
Plugin
SERVERSIDECLIENTSIDE
DIG 1.2 + OBDA
Extension
TBox
DS Info +
Mappings
QuOnto
DIG Server for
QuOnto
DS Info +
Mappings
TBox
RDBMS
<?xml version="1.0"
encoding="ISO-8859-1"?>
<tells xmlns="http://dl.kr.org/dig/lang"
xmlns:xsi="http://www.w3.org/2001/
XMLSchema-instance"
xsi:schemaLocation="http://wasp.cs.vu.nl/
sekt/digtest/dig-1.1.xsd">
<clearKB/>
<defconcept name="a"/>
<impliesc>
<catom name="a"/>
<and>
<not>
<or>
<catom name="b"/>
<catom name="c"/>
</or>
</not>
</and>
</impliesc
</tells>
Thursday, August 8, 13

28. First steps
Protégé
Protégé
OWLPlugin
OBDA
Plugin
SERVERSIDECLIENTSIDE
DIG 1.2 + OBDA
Extension
TBox
DS Info +
Mappings
QuOnto
DIG Server for
QuOnto
DS Info +
Mappings
TBox
RDBMS
DIG Server for
QuOnto
<?xml version="1.0"
encoding="ISO-8859-1"?>
<tells xmlns="http://dl.kr.org/dig/lang"
xmlns:xsi="http://www.w3.org/2001/
XMLSchema-instance"
xsi:schemaLocation="http://wasp.cs.vu.nl/
sekt/digtest/dig-1.1.xsd">
<clearKB/>
<defconcept name="a"/>
<impliesc>
<catom name="a"/>
<and>
<not>
<or>
<catom name="b"/>
<catom name="c"/>
</or>
</not>
</and>
</impliesc
</tells>
Thursday, August 8, 13

29. First steps
Protégé
Protégé
OWLPlugin
OBDA
Plugin
SERVERSIDECLIENTSIDE
DIG 1.2 + OBDA
Extension
TBox
DS Info +
Mappings
QuOnto
DIG Server for
QuOnto
DS Info +
Mappings
TBox
RDBMS
DIG Server for
QuOnto
OBDA Plugin
for Protégé
<?xml version="1.0"
encoding="ISO-8859-1"?>
<tells xmlns="http://dl.kr.org/dig/lang"
xmlns:xsi="http://www.w3.org/2001/
XMLSchema-instance"
xsi:schemaLocation="http://wasp.cs.vu.nl/
sekt/digtest/dig-1.1.xsd">
<clearKB/>
<defconcept name="a"/>
<impliesc>
<catom name="a"/>
<and>
<not>
<or>
<catom name="b"/>
<catom name="c"/>
</or>
</not>
</and>
</impliesc
</tells>
Thursday, August 8, 13

30. Demo, Ontology
StockBroker
Trader
StockExchangeMember
Investor
Dealer StockTrader
tradesOnBehalfOf
usesBroker
Person
1 .. *
<<ident>>financialInstrumentID: int
FinancialInstrument
<<ident>listdate: date
StockExchangeList
<<ident>transactionID:int
transactionDate: Date
Transaction
amountOfShares: int
typeOfShares: Boolean
Stock 1 .. *0 .. *
listsStock
StockExchangeMember
isExecutedBy
1 .. 1
Company
involvesInstrument
isTradedIn
1 .. 1
0 .. 1
Acquisition Offer
isListedIn
1 .. 1 0 .. *
hasStock
belongsToCompany
{disjoint}
Investor
isExecutedFor1 .. 1
companyName: String
marketShares: Integer
netWorth: Real
Company
firstName: Name
lastName: String
dateOfBirth: Date
ssn: String
PhysicalPersonLegalPerson
<<ident>personID: int
Person
<<ident>addressID: int
inStreet: Sring
hasNumber: Int
inCity: String
inState: String
inCountry: String
Address
1 .. *
1 .. 1
hasAddress{disjoint}
Thursday, August 8, 13

31. Demo, scenario 1
core services
Client
addressid
......
dateofbirth ssnid
...
lastname
...... ...
name
Broker
addressid
...... ...
name ssn
......
id
...
lastname dateofbirth
BrokerWorksFor
...... ...
brokerid companyid clientid
Company
...
addressid
...
id
...
name
...
networthmarketshares
...
Transaction
......
id
...... ...
brokerid forclientidtype forcompanyiddate stockid
... ...
StockBookList
date
...
stockid
...
Address
country
...
state
......
id
...
street
...
citynumber
...
StockInformation
...
companyid
...
sharetypeid
...
numberofshares
...
Thursday, August 8, 13

32. Demo, Ontology
StockBroker
Trader
StockExchangeMember
Investor
Dealer StockTrader
tradesOnBehalfOf
usesBroker
Person
1 .. *
<<ident>>financialInstrumentID: int
FinancialInstrument
<<ident>listdate: date
StockExchangeList
<<ident>transactionID:int
transactionDate: Date
Transaction
amountOfShares: int
typeOfShares: Boolean
Stock 1 .. *0 .. *
listsStock
StockExchangeMember
isExecutedBy
1 .. 1
Company
involvesInstrument
isTradedIn
1 .. 1
0 .. 1
Acquisition Offer
isListedIn
1 .. 1 0 .. *
hasStock
belongsToCompany
{disjoint}
Investor
isExecutedFor1 .. 1
companyName: String
marketShares: Integer
netWorth: Real
Company
firstName: Name
lastName: String
dateOfBirth: Date
ssn: String
PhysicalPersonLegalPerson
<<ident>personID: int
Person
<<ident>addressID: int
inStreet: Sring
hasNumber: Int
inCity: String
inState: String
inCountry: String
Address
1 .. *
1 .. 1
hasAddress{disjoint}
Thursday, August 8, 13

33. Mappings, populating
concepts
Address(getAddressObj($address.id))
select * from address;
Thursday, August 8, 13

34. Mappings, populating attributes
(datatype properties)
Address(getAddressObj($address.id)),
addressID(getAddressObj($address.id),$address.id)
select * from address;
Thursday, August 8, 13

35. Mappings, populating roles
(object properties)
hasAddress(getPersonObj($broker.id),getAddressObj($broker.addressid))
select * from broker;
Thursday, August 8, 13

36. Scenario II, conceptual
model extraction
Thursday, August 8, 13

37. Scenario II, conceptual
model extraction
shares: int
<<ident> id: int
Stock_Unit
1 .. 1
Stock_Company
average: int
<<ident>date: date
Transaction_List1 .. *
0 .. *
Stock_TransactionList
descr: string
date: date
<<ident> id: int
Purchase
descr: string
date: date
<<ident> id: int
Sale
Purchase_Stock
0 .. *
descr: string
date: date
<<ident> id: int
Stock_Exchange_
Company
1 .. 1
Sale_Stock
0 .. 10 .. 1 1 .. 1
type: string
name: string
<<ident> id: int
Broker
name: string
<<ident> id: int
Share_Holder
1 .. 11 .. 1 Broker_SaleBroker_Purchase
1 .. *
Share_Holder_Broker
Thursday, August 8, 13

38. Scenario II, conceptual
model extraction
STOCK_UNIT
...... ...
company_idsharesid
PURCHASE
broker_id
......
stock_iddescr
......
date
...
id
SALE
broker_id
......
stock_iddescr
......
date
...
id
TRANSACTION_LIST
... ...
averagedate
...
stock_id
...
trans_date
STOCK_TRANSACTIONLISTSTOCK_EXCHANGE_COMPANY
shares
......... ...
networthnameid
BROKER
...... ...
typenameid
TRADER_CLIENT
...... ...
broker_idnameid
Thursday, August 8, 13

39. Scenario II, conceptual
model extraction
STOCK_UNIT
...... ...
company_idsharesid
PURCHASE
broker_id
......
stock_iddescr
......
date
...
id
SALE
broker_id
......
stock_iddescr
......
date
...
id
TRANSACTION_LIST
... ...
averagedate
...
stock_id
...
trans_date
STOCK_TRANSACTIONLISTSTOCK_EXCHANGE_COMPANY
shares
......... ...
networthnameid
BROKER
...... ...
typenameid
TRADER_CLIENT
...... ...
broker_idnameid
Thursday, August 8, 13

40. Scenario II, conceptual
model extraction
STOCK_UNIT
...... ...
company_idsharesid
PURCHASE
broker_id
......
stock_iddescr
......
date
...
id
SALE
broker_id
......
stock_iddescr
......
date
...
id
TRANSACTION_LIST
... ...
averagedate
...
stock_id
...
trans_date
STOCK_TRANSACTIONLISTSTOCK_EXCHANGE_COMPANY
shares
......... ...
networthnameid
BROKER
...... ...
typenameid
TRADER_CLIENT
...... ...
broker_idnameid
shares: int
<<ident> id: int
Stock_Unit
1 .. 1
Stock_Company
average: int
<<ident>date: date
Transaction_List1 .. *
0 .. *
Stock_TransactionList
descr: string
date: date
<<ident> id: int
Purchase
descr: string
date: date
<<ident> id: int
Sale
Purchase_Stock
0 .. *
descr: string
date: date
<<ident> id: int
Stock_Exchange_
Company
1 .. 1
Sale_Stock
0 .. 10 .. 1 1 .. 1
type: string
name: string
<<ident> id: int
Broker
name: string
<<ident> id: int
Share_Holder
1 .. 11 .. 1 Broker_SaleBroker_Purchase
1 .. *
Share_Holder_Broker
Thursday, August 8, 13

41. Final Remarks
• Plugin and server are now going trough extensive testing
• Public releases of both tools will happen by the end of april
• The software will be downloadable from
• http://www.inf.unibz.it/~rodriguez/obda/
• Future work: Explanations for all inferences and queries,
Extending Protege/DIG with more expressivity regarding
roles.
Thursday, August 8, 13