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Semi-Automatic Example-Driven
Linked Data Mapping Creation
Pieter Heyvaert
pheyvaer.heyvaert@ugent.be
1
Semantic Web technologies rely on Linked Data,
but not all data is accessible as Linked Data.
databases
XML files
Solution...
Goal: improve access to data as Linked Data
3
Overview
problem
current solutions
approach
discussion
4
Overview
problem
current solutions
approach
discussion
5
Input data
id title author
0 Harry Potter and The Sorcerer’s Stone J.K. Rowling
1 Homo Deus Yuval Noah Harari
{
"authors":...
Desired Linked Data
book:0 a schema:Book;
schema:title "Harry Potter and The Sorcerer’s Stone"@en;
schema:author author:jk...
Apply rules to generate Linked Data
original
data
Linked
Data
rules
rules state how to generate RDF terms and triples usin...
Linked Data example available
9
book:1 a schema:Book;
schema:title "Homo Deus"@en;
schema:author author:ynh.
author:ynh a ...
Use example to create rules
sample example
rules
10
original
data
Linked
Data
Linked Data example aligns
with sample of original data
id title author
1 Homo Deus Yuval Noah Harari
{
"id": "ynh",
"name...
Alignment with original data and create rules
book:1 a schema:Book;
schema:title "Homo Deus"@en;
schema:author author:ynh....
Alignment with original data and create rules
book:1 a schema:Book;
schema:title "Homo Deus"@en;
schema:author author:ynh....
Alignment with original data and create rules
book:1 a schema:Book;
schema:title "Homo Deus"@en;
schema:author author:ynh....
Alignment with original data and create rules
book:1 a schema:Book;
schema:title "Homo Deus"@en;
schema:author author:ynh....
Alignment with original data and create rules
book:1 a schema:Book;
schema:title "Homo Deus"@en;
schema:author author:ynh....
All rules
IRI is “book” + value from column “id”
Literal uses value from column “title”
Predicate is schema:title
Type of ...
Apply rules to generate all Linked Data
sample example
rules
18
original
data
Linked
Data
Linked Data might not be as desired
Rules are prone to errors when created manually
Wrong use of ontology classes, propert...
Overview
problem
current solutions
approach
discussion
20
Overview
problem
current solutions
approach
discussion
21
Solutions to reduce manual effort
when creating rules
Semi-automatic: users provide feedback
Automatic: no user interactio...
Current solutions use limited knowledge
Only work with
data schemas
data values
ontologies
Do not consider knowledge embed...
Overview
problem
current solutions
approach
discussion
24
Overview
problem
current solutions
approach
discussion
25
We propose a semi-automatic
example-driven approach to create rules.
26
Overview
problem
current solutions
approach
data source alignment
rule creation
optional adjustments
Linked Data generatio...
book:1 a schema:Book;
schema:title "Homo Deus"@en;
schema:author author:ynh.
Visualize Linked Data example
author:ynh a fo...
Overview
problem
current solutions
approach
data source alignment
rule creation
optional adjustments
Linked Data generatio...
Overview
problem
current solutions
approach
data source alignment
rule creation
optional adjustments
Linked Data generatio...
{
"id": "ynh",
"name": "Yuval Noah Harari",
"country": "Israel",
"birthdate": "1976-04-24"
}
Align with data sources
schem...
{
"id": "ynh",
"name": "Yuval Noah Harari",
"country": "Israel",
"birthdate": "1976-04-24"
}
Align with data sources
schem...
{
"id": "ynh",
"name": "Yuval Noah Harari",
"country": "Israel",
"birthdate": "1976-04-24"
}
Align with data sources
schem...
Align with data sources
schema:Book foaf:Person
Homo Deus
@en
Yuval Noah Harari Israel 1976-04-24
xsd:date
book:1 author:y...
Select best data source
schema:Book foaf:Person
Homo Deus
@en
Yuval Noah Harari Israel 1976-04-24
xsd:date
book:1 author:y...
Select best data source
schema:Book foaf:Person
Homo Deus
@en
Yuval Noah Harari Israel 1976-04-24
xsd:date
book:1 author:y...
Select best data source
schema:Book foaf:Person
Homo Deus
@en
Yuval Noah Harari Israel 1976-04-24
xsd:date
book:1 author:y...
Overview
problem
current solutions
approach
data source alignment
rule creation
optional adjustments
Linked Data generatio...
Rule creation
For every entity
For every attribute
For all interlinked entities
39
Create rules for entity
schema:Book
book:1
CSV
IRI is “book” + id
type is schema:Book
40
Create rules for attribute
schema:Book
book:1
CSVuse predicate schema:title
literal uses value from column title
language ...
Create rules for interlinked entities
schema:Book
book:1
CSV
use predicate schema:author
join condition: names match
foaf:...
Overview
problem
current solutions
approach
data source alignment
rule creation
optional adjustments
Linked Data generatio...
Optional adjustments
Fix errors if needed
Add additional rules to deal with exceptions
44
Overview
problem
current solutions
approach
data source alignment
rule creation
optional adjustments
Linked Data generatio...
Apply rules to generate all Linked Data
sample example
46
original
data
Linked
Data
rules
Overview
problem
current solutions
approach
data source alignment
rule creation
optional adjustments
Linked Data generatio...
Discussion
Advantages
Use knowledge embedded in Linked Data examples
Minimize errors and user interaction
Approach can be ...
Recap
Use cases can have Linked Data example available.
Example contains knowledge to create rules.
We introduced approach...
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Semi-Automatic Example-Driven Linked Data Mapping Creation

Linked Data can be generated by applying mapping rules on existing (semi-)structured data. The manual creation of these rules involves a costly process for users. Therefore, (semi-)automatic approaches have been developed to assist users. Although, they provide promising results, in use cases where examples of the desired Linked Data are available they do not use the knowledge provided by these examples, resulting in Linked Data that might not be as desired. This in turn requires manual updates of the rules. These examples can in certain cases be easy to create and offer valuable knowledge relevant for the mapping process, such as which data corresponds to entities and attributes, how this data is an- notated and modeled, and how different entities are linked to each other. In this paper, we introduce a semi-automatic approach to create rules based on examples for both the existing data and corresponding Linked Data. Furthermore, we made the approach available via the RMLEditor, making it readily accessible for users through a graphical user interface. The proposed approach provides a first attempt to generate a complete Linked Dataset based on user-provided examples, by creating an initial set of rules for the users.

https://pieterheyvaert.com/research/publications/heyvaert_ld4ie_2017/

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Semi-Automatic Example-Driven Linked Data Mapping Creation

  1. 1. Semi-Automatic Example-Driven Linked Data Mapping Creation Pieter Heyvaert pheyvaer.heyvaert@ugent.be 1
  2. 2. Semantic Web technologies rely on Linked Data, but not all data is accessible as Linked Data. databases XML files Solutions to provide access exist, but results are not always as desired because limited knowledge is used: data schema ontology 2
  3. 3. Goal: improve access to data as Linked Data 3
  4. 4. Overview problem current solutions approach discussion 4
  5. 5. Overview problem current solutions approach discussion 5
  6. 6. Input data id title author 0 Harry Potter and The Sorcerer’s Stone J.K. Rowling 1 Homo Deus Yuval Noah Harari { "authors": [{ "id": "jkr", "name": "J.K. Rowling", "country": "UK" "birthdate": "1965-07-31" },{ "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" }] } 6
  7. 7. Desired Linked Data book:0 a schema:Book; schema:title "Harry Potter and The Sorcerer’s Stone"@en; schema:author author:jkr. book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. author:jkr a foaf:Person; foaf:name "J.K. Rowling"; foaf:country "UK"; schema:birthdate "1965-07-21"^^xsd:date. author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "UK"; schema:birthdate "1976-04-24"^^xsd:date. 7
  8. 8. Apply rules to generate Linked Data original data Linked Data rules rules state how to generate RDF terms and triples using data and ontologies 8
  9. 9. Linked Data example available 9 book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "Israel"; schema:birthdate "1976-04-24"^^xsd:date.
  10. 10. Use example to create rules sample example rules 10 original data Linked Data
  11. 11. Linked Data example aligns with sample of original data id title author 1 Homo Deus Yuval Noah Harari { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } 11 book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "Israel"; schema:birthdate "1976-04-24"^^xsd:date.
  12. 12. Alignment with original data and create rules book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "Israel"; schema:birthdate "1976-04-24"^^xsd:date. id title author 1 Homo Deus Yuval Noah Harari { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } id 12 rule: IRI is “book” + value from column “id”
  13. 13. Alignment with original data and create rules book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "Israel"; schema:birthdate "1976-04-24"^^xsd:date. id title author 1 Homo Deus Yuval Noah Harari { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } title 13 rule: literal uses value from column “title”
  14. 14. Alignment with original data and create rules book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "Israel"; schema:birthdate "1976-04-24"^^xsd:date. id title author 1 Homo Deus Yuval Noah Harari { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } titleproperty 14 rule: predicate is schema:title
  15. 15. Alignment with original data and create rules book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "Israel"; schema:birthdate "1976-04-24"^^xsd:date. id title author 1 Homo Deus Yuval Noah Harari { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } type 15 rule: type of a book is schema:Book
  16. 16. Alignment with original data and create rules book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "Israel"; schema:birthdate "1976-04-24"^^xsd:date. id title author 1 Homo Deus Yuval Noah Harari { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } other entity 16 rule: a book is related to its author
  17. 17. All rules IRI is “book” + value from column “id” Literal uses value from column “title” Predicate is schema:title Type of a book is schema:Book A book is related to its author 17
  18. 18. Apply rules to generate all Linked Data sample example rules 18 original data Linked Data
  19. 19. Linked Data might not be as desired Rules are prone to errors when created manually Wrong use of ontology classes, properties, and datatypes Wrong alignments with original data Especially when dealing with large and complex data sources multiple data sources at the same time 19
  20. 20. Overview problem current solutions approach discussion 20
  21. 21. Overview problem current solutions approach discussion 21
  22. 22. Solutions to reduce manual effort when creating rules Semi-automatic: users provide feedback Automatic: no user interaction required 22
  23. 23. Current solutions use limited knowledge Only work with data schemas data values ontologies Do not consider knowledge embedded in query workload of Linked Data Linked Data examples 23
  24. 24. Overview problem current solutions approach discussion 24
  25. 25. Overview problem current solutions approach discussion 25
  26. 26. We propose a semi-automatic example-driven approach to create rules. 26
  27. 27. Overview problem current solutions approach data source alignment rule creation optional adjustments Linked Data generation discussion 27
  28. 28. book:1 a schema:Book; schema:title "Homo Deus"@en; schema:author author:ynh. Visualize Linked Data example author:ynh a foaf:Person; foaf:name "Yuval Noah Harari"; foaf:country "Israel"; schema:birthdate "1976-04-24"^^xsd:date. schema:Book foaf:Person Homo Deus @en Yuval Noah Harari Israel 1976-04-24 xsd:date book:1 author:ynh schema:author schema:title foaf:name schema:birthdate foaf:country 28
  29. 29. Overview problem current solutions approach data source alignment rule creation optional adjustments Linked Data generation discussion 29
  30. 30. Overview problem current solutions approach data source alignment rule creation optional adjustments Linked Data generation discussion 30
  31. 31. { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } Align with data sources schema:Book foaf:Person Homo Deus @en Yuval Noah Harari Israel 1976-04-24 xsd:date book:1 author:ynh schema:author schema:title foaf:name schema:birthdate foaf:country id title author 1 Homo Deus Yuval Noah Harari CSV JSON 31
  32. 32. { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } Align with data sources schema:Book foaf:Person Homo Deus @en Yuval Noah Harari Israel 1976-04-24 xsd:date book:1 author:ynh schema:author schema:title foaf:name schema:birthdate foaf:country id title author 1 Homo Deus Yuval Noah Harari CSV CSV JSON 32
  33. 33. { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } Align with data sources schema:Book foaf:Person Homo Deus @en Yuval Noah Harari Israel 1976-04-24 xsd:date book:1 author:ynh schema:author schema:title foaf:name schema:birthdate foaf:country id title author 1 Homo Deus Yuval Noah Harari CSV CSV CSV JSON 33
  34. 34. Align with data sources schema:Book foaf:Person Homo Deus @en Yuval Noah Harari Israel 1976-04-24 xsd:date book:1 author:ynh schema:author schema:title foaf:name schema:birthdate foaf:country JSONCSV CSV CSV JSON JSON JSON { "id": "ynh", "name": "Yuval Noah Harari", "country": "Israel", "birthdate": "1976-04-24" } id title author 1 Homo Deus Yuval Noah Harari CSV JSON 34
  35. 35. Select best data source schema:Book foaf:Person Homo Deus @en Yuval Noah Harari Israel 1976-04-24 xsd:date book:1 author:ynh schema:author schema:title foaf:name schema:birthdate foaf:country JSONCSV CSV CSV JSON JSON JSON for each subgraph with an entity 35
  36. 36. Select best data source schema:Book foaf:Person Homo Deus @en Yuval Noah Harari Israel 1976-04-24 xsd:date book:1 author:ynh schema:author schema:title foaf:name schema:birthdate foaf:country JSONCSV CSV CSV JSON JSON JSON only CSV data source CSV 36
  37. 37. Select best data source schema:Book foaf:Person Homo Deus @en Yuval Noah Harari Israel 1976-04-24 xsd:date book:1 author:ynh schema:author schema:title foaf:name schema:birthdate foaf:country JSONCSV CSV CSV JSON JSON JSON CSV data source match with 1 node JSON data source match with all nodes JSON 37
  38. 38. Overview problem current solutions approach data source alignment rule creation optional adjustments Linked Data generation discussion 38
  39. 39. Rule creation For every entity For every attribute For all interlinked entities 39
  40. 40. Create rules for entity schema:Book book:1 CSV IRI is “book” + id type is schema:Book 40
  41. 41. Create rules for attribute schema:Book book:1 CSVuse predicate schema:title literal uses value from column title language of the title is English Homo Deus @en schema:title CSV 41
  42. 42. Create rules for interlinked entities schema:Book book:1 CSV use predicate schema:author join condition: names match foaf:Person author:ynh schema:author JSON 42
  43. 43. Overview problem current solutions approach data source alignment rule creation optional adjustments Linked Data generation discussion 43
  44. 44. Optional adjustments Fix errors if needed Add additional rules to deal with exceptions 44
  45. 45. Overview problem current solutions approach data source alignment rule creation optional adjustments Linked Data generation discussion 45
  46. 46. Apply rules to generate all Linked Data sample example 46 original data Linked Data rules
  47. 47. Overview problem current solutions approach data source alignment rule creation optional adjustments Linked Data generation discussion 47
  48. 48. Discussion Advantages Use knowledge embedded in Linked Data examples Minimize errors and user interaction Approach can be combined with other approaches Disadvantages Linked Data example is required User action might still be required for special cases 48
  49. 49. Recap Use cases can have Linked Data example available. Example contains knowledge to create rules. We introduced approach that uses this knowledge. This approach can be combined with other approaches. 49

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