1. Copyright: SIPC From Ontology to Data Model: Choices and Design Decisions Matthew West Reference Data Architecture and Standards Manager Shell International Petroleum Company Ontolog Forum Database and Ontology mini-series Session-2 16-Nov-2006

2. 2 Introduction An ontology describes the types of things that exist, and rules that govern them, a data model defines records about things, and is the basis for a database design. Not all the information in an ontology may be needed (or can even be held) in a data model and there are a number of choices that need to be made. For example, some of the ontology may be held as reference data instead of as entity types. This talk will explore these choices, with illustrations from the ISO 15926-2 data model.

3. 3 Relationship between an Ontology and Enterprise Systems Ontology – Rules – Classes – Objects Enterprise Systems – Business Processes (manuals) – Application Processes and Stored Procedures – Database Structure – Records

4. 4 Relationship between an Ontology and Enterprise Systems Ontology – Rules – Classes – Objects Enterprise Systems – Business Processes (manuals) – Application Processes and Stored Procedures – Database Structure – Records

5. 5 Relationship between an Ontology and Enterprise Systems Ontology – Rules – Classes – Objects Enterprise Systems – Business Processes (manuals) – Application Processes and Stored Procedures – Database Structure – Records

6. 6 Relationship between an Ontology and Enterprise Systems Ontology – Rules – Classes – Objects Enterprise Systems – Business Processes (manuals) – Application Processes and Stored Procedures – Database Structure – Records

7. 7 Relationship between an Ontology and Enterprise Systems Ontology – Rules – Classes – Individuals Enterprise Systems – Business Processes (manuals) – Application Processes and Stored Procedures – Database Structure – Records Harder (more expensive) to change Easier to enforce limited

8. 8 Data Models: Capabilities and Limitations thing Xclass of X some X some other X Subtype/ supertype relationship member of

9. 9 Data Models: Capabilities and Limitations thing Xclass of X some X some other X Subtype/ supertype relationship Member of relationship My X a member of My class of X

10. 10 Data Models: Capabilities and Limitations thing Xclass of X some X some other X Subtype/ supertype relationship Member of relationship My X a member of My class of X

11. 11 Data Models: Some Options thing Xclass of X Subtype of member of

12. 12 Data Models: Some options thing Xclass of X Subtype of X some X some other X member of

13. 13 Data Models: Some options thing class of X Subtype of X some X some other X

14. 14 Reference Data Model and the Business Information Model level

15. 15 A (3D) Logical Data Model for some Reference Data Identification Start Date End Date ThingName String Product Date Introduced Date Withdrawn Market Start Date End Date Brand Date Introduced Date Withdrawn Selling of product under Brand Start Date End Date Selling of product in Market Start Date End Date ofidentifier inof under Product Price Value Start Date End Date Currency Start Date End Date in for

16. 16 A denormalized Physical Data Model for Product, Brand, and Market

17. 17 A Generic Physical Data Model for Reference Data

18. 18 Some Data Modelling Choices made in ISO 15926-2 Relations modelled as entity types (not attributes) Key entity types for 4D paradigm included Subtypes of X not held when they can be held as instances of class_of_X, especially when numbers of subtypes are large Explicit model of representation (names and numbers) included to support multiple names and descriptions Meta-model included for extensibility, the ontology makes an open world rather than closed world assumption

19. 19 Some choices made in ISO 15926 (ABS) thing 1 6,1 possible_individual (ABS) abstract_object 2,1 class 18,2 representation_of_Gregorian_date_and_UTC_time 17,1 class_of_information_representation 11,1 relationship 4,1 multidimensional_ object *id STRING record_copy_created record_created record_creator record_logically_deleted why_deleted

20. 20 Some choices made in ISO 15926 possible_ individual arranged_ individual 9,1 event period_in_time physical_object materialized_ physical_object functional_ physical_object stream spatial_location 9,2 activity actual_individual whole_life_ individual composition_of_ individual 1 arrangement_ of_individual 1 assembly_of_ individual feature_whole_ part (RT) whole whole temporal_ whole_part 9,3 participation 9,4 temporal_bounding part Note: has no subtypes

21. 21 Some choices made in ISO 15926 class_of_arranged_ individual 1 class_of_atom phase class_of_biological_ matter class_of_functional_ object class_of_compound class_of_molecule class_of_composite_ material crystalline_structure class_of_sub_atomic_ particle class_of_information_ presentation 17,1 class_of_information_ representation class_of_particulate_ material class_of_ organization 10,1 class_of_ activity class_of_ information_object class_of_feature 1 class_of_organism class_of_person class_of_ inanimate_ physical_object Subtypes of arranged_individual can be found here as instances

22. 22 The split of classes between entity types and instances in ISO 15926 ISO 15926-2 Generic Classes Standard Classes Proprietary Classes Data Model (201 classes) Reference Data Library Standard and Proprietary classes (some 24,000 classes currently under development) Reference Data Library generic classes (some 10,000 classes due for publication as ISO 15926- 4)

23. 23 Representation (by e.g. text or numbers) 6,1 possible_individual representation_ of_thing definition (RT) represented represented 1,1 thing 2,1 class identification description sign usage_of_ representation used user responsibility_ for_ representation controlled controller e.g. piece of paper with text on it.

24. 24 Class of representation 6,1 possible_individual class_of_ information_ representation 1 18,1 class_of_EXPRESS_information_representation 18,2 representation_of_Gregorian_date_and_UTC_time class_of_ representation_ translation class_of_first class_of_second class_of_usage_ of_representation class_of_used class_of_ representation_ of_thing class_of_ identification class_of_ definition (RT) represented represented 1,1 thing 2,1 class class_of_ description pattern user class_of_ responsibility_for_ representation class_of_controlled controller e.g. the text on one or more pieces of paper.

25. 25 Part of the Meta-Model class specialization subclass superclass classification classified 1,1 thing classifier

26. 26 Another part of the Meta-Model role_and_domain role class_of_ relationship_ with_signature specialization_ by_domain (RT) subclass specialization_ by_role (RT) subclass (RT) superclass class_of_end_1 class_of_end_2

27. 27 From Data Model to Database - Considerations First cut, each entity type maps to a table, but only if – Each table has some distinct attributes, or – There is some reason to segregate records (volume or access requirements)

28. 28 From Data Model to Database possible_ individual arranged_ individual 9,1 event period_in_time physical_object materialized_ physical_object functional_ physical_object stream spatial_location 9,2 activity actual_individual whole_life_ individual

29. 29 From Data Model to Database possible_ individual arranged_ individual 9,1 event period_in_time physical_object materialized_ physical_object functional_ physical_object stream spatial_location 9,2 activity actual_individual whole_life_ individual PossibleIndividuals IsWholeLifeIndividual IsActualIndividual IsArrangedIndividual IsEvent IsPeriodInTime IsActivity IsPhysicalObject IsFunctionalPhysicalMateri al IsStream IsSpatialLocation

30. 30 Conclusions Data Models are a key component for getting ontologies used in Information Systems There are a wide range of options when making design decisions both in moving from Ontology to Data Model/Reference Data, and from Data Model to Database Which options are best is likely to depend on the particular circumstances of and purposes of an application