Ram Kumar Chairman OASIS CIQ Technical Committee

1. Using Code List Methodology for Value and Validation (from OASIS Code List Representation and UBL TCs) in OASIS CIQ Specifications V3.0– A Case Study Ram Kumar Chairman OASIS CIQ Technical Committee http://www.oasis-open.org/committees/ciq June 2007

2. Agenda • Code List • What, Why, Standard • OASIS Code List Representation TC • OASIS UBL Methodology for Code List Value and Validation (UMCLVV) from OASIS UBL TC • OASIS CIQ TC Implementation of OASIS Code List Specifications – A Case Study

3. What is a Code List?aka enumerations, aka controlled vocabularies aka classification scheme and classification values • A set of values to choose from which represent an agreed upon semantic concept • Days of a week = {“Mon”, “Tue”, “Wed”, “Thu”, “Fri”, “Sat”, “Sun”} • Code List = List Name + values • List Name = Days of a week • Values = {“Mon”, “Tue”, “Wed”, “Thu”, “Fri”, “Sat”, “Sun”}

4. Why Code Lists are important? • It is not just elements and attribute names in XML that need to be semantically unambiguous & aligned for interoperability • The lexical form of element and attribute text content also needs to be aligned, i.e. simple data items need to be represented the same way • This is more important for applications • For data oriented XML particularly (e.g. CIM), Code Lists are as important as elements and attributes – they form part of the complete vocabulary of the document

5. Standard for Code List • If code lists were really so simple and obvious, there would be a single, well known and acceptable way of handling them in XML • There is no agreed solution, though • The problem is that while code lists are a well understood concept, people do not actually agree on exactly what code lists are, and how they should be used

6. The code list is in the eyes of the beholder • The XML schema may require only a 3-letter codes to represent the code list • The database may require a set of numeric codes, plus display labels (possibly in different languages) • The application may need to know which 3-letter code corresponds to which numeric code, so that it can process the XML and update the database • All of this code list information needs to be stored together in a single representation of the code list, so that all usages of code list can be generated from the same source information

7. The only constant is change • Code lists change • For a code list model to be useful, it has to account for the fact that the code lists will change over time • There is little use in having a code list model that works only for a code list that is frozen in time • The code list model has to support changes between versions of a code list

8. The only constant is change • Not all changes to a code list are version changes, however • Some changes may be local changes to a distributed code list • The ISO 3-letter currency code list contains GBP for British Pounds. However, prices on the London Stock Exchange are normally quoted in pence • This has led to the practice of adding an extra code to the standard ISO list (e.g. GBp, GBX) in order support pence as well as pounds • This kind of customisation is far from uncommon • The utility of any code list model is greatly reduced if it does not cater for local modifications of code lists

9. OASIS Code List Representation Technical Committee • The OASIS Code List Representation format, “genericode”, is a single model and XML format (with a W3C XML Schema) that can encode a broad range of code list information • The XML format is not designed for run-time orreal-time use, but to have the standardizedinterchange format massaged into an optimized representation • 27 of the 40 requirements gathered are implemented in v1.0 of the specifications

10. Genericode Model • Has a tabular structure for code list information • Each row in the table represents a single distinct entry in the code list, i.e. each row represents a single uniquely identifiable item in the code list. • Each column in the table represents a metadata value that can be defined for each distinct entry in the code list. Each column is either required or optional. A required column does not allow any row to have an undefined (nil or null) value. An optional column allows undefined values. • A genericode key is a set of one or more required columns that together uniquely identify each distinct entry in the code list. Optional columns cannot be used for keys. Each code list must have at least one key. • Genericode keys are equivalent to what people usually mean when they talk about the “codes” in a code list. However, genericode allows multiple keys for each code list, and there is no single preferred key.

11. Concept • Keep code lists aka enumerations out of the core XML schema by using “schemes” • The idea is that the code lists from which an element value is taken is indicated via a “scheme” attribute containing a URI which represents the scheme (code list) • Same as the way that URIs are used to represent XML namespaces • This is done so that a newer version of core XML schema need not be released just because an externally controlled enumeration that it uses has changed (e.g. country code)

12. OASIS UBL Methodology forCode List and Value Validation(UMCLVV 0.8)

13. Graphical Schema View: XML instance documents can be validated against the applicable XML Schema Text view of XML instance: XMLinstanceXXX.xml<StsMetadataRecord>xsi:schemaLocation="urn:oasis:names:tc:ciq:xNL:3 ” <ESLVersionNumberID>5.0</ESLVersionNumberID> <Person> <cbc:BirthDate>1967-08-13</cbc:BirthDate> <LearnerRegistration> <cbc:NationalStudentNumberID>123456</cbc:NationalStudentNumberID> </LearnerRegistration> <PersonNameGeneric> <cbc:FirstName>John</cbc:FirstName> <cbc:LastName>Smith</cbc:LastName> </PersonNameGeneric> . . . XML Instance Document Validation Namespace: xmlns="urn:oasis:names:tc:ciq:xNL:3

14. Background (Glossary) • XML Data ContentIn an XML instance document, any values- between XML angles ‘>’ and ‘<’ and- between quotes of an attribute are message data content Examples: <BirthDate>1960-06-09</BirthDate> <Country> <CountryCode listSchemeURI=" urn:oasis:names:tc:ciq:xNL:3:codelist:gc:Country-1“>AUS</CountryCode> <Name>Australia</Name> </Country>

15. Background (Glossary), continued Types of XML data content: • Code values • Other values (non-code values) Examples: <Country> <CountryCode>AUS</CountryCode> </Country> <BirthDate>1960-06-09</BirthDate>

16. W3C XML Schema Limitations W3C XML Schema is mostly about data structures But it does some Data Content Validation • has good support for - data type conformity- min/max values- length, patterns … • has limited support for:- enumerations • has no support for- complex business rules- versioned changes of validation (without affecting the Schema’s version)

17. Business Rules Examples • Date Arithmetic:BirthDate < CurrentDate – 6 Years • Attribute Value Restriction: The code list value “First Name” cannot occur more than once The code list value “Last Name” cannot occur more than once • Element Use Restriction Country element cannot occur more than once, but optional • Zero-length string:<Name></Name>

18. Business Rules Examples, continued • Code Liststhe code list (+version) used by CountryCode must be an accepted code list<CountryCode listSchemeURI="urn:oasis:names:tc:ciq:xNL:3:codelist:gc:Country-1“>AUS</CountryCode> • Code ValueCountryCode ‘XYZ’ must be valid in that Country code list version <CountryCode listSchemeURI=" urn:oasis:names:tc:ciq:xNL:3:codelist:gc:Country-1“>AUS</CountryCode> • Co-occurrenceif Status=‘Closed’ then ClosureReason must be present also<StatusCode>Closed</StatusCode><ClosureReason>Obsolete</ClosureReason>

19. Data Content Validation Conclusion • XML Schema does not cover all data content validation requirements • Embedding content validation in XML Schema has undesired consequences in conjunction with re-use and Schema versioning • Business rules vary more frequently than schema constraints, and the business rules between different partners wouldvary where the schema constraints remain the same. • By layering value constraints on top of structural/ lexical constraints, the schemas can remain unchanged while being adapted to different partners through different value constraints • Is data content validation required ? • How can data content be validated in XML instances ?

20. DesignImplementation Content Validation at A: Content Validation at B: - Program code - Program code - Database constraints - Database constraints Interoperability issues: • Validation at A equivalent to Validation at B? • Data quality of message is difficult to control • Communication of data quality issues between A & B • Relies on trust in the sender • Hard to ascertain equal interpretation of codes Without Data Content Validation in XML Data Exchange Partner Agreement Schema Validation W3C XML Document Schema A A A 00101101 B XML file extends

21. DesignImplementation With Data Content Validation in XML Data Exchange Partner Agreement Sender’s and receiver's data content validation must be - electronic - portable- of shared logic and error output- platform-independent- versioned 1. Schema Validation W3C XML Document Schema A A A 00101101 B XML file extends 2. Content Validation XML Content Validation

22. DesignImplementation With Data Content Validation in XML Data Exchange Partner Agreement Sender’s and receiver's data content validation must be - electronic - portable- of equivalent logic and error output- platform-independent- versioned 1. Schema Validation W3C XML Document Schema A A A 00101101 B XML file extends 2. Content Validation UMCLVV

23. UMCLVV Features • Code Value ValidationExample:CountryCode must be a valid CountryCode • Code List Metadata ValidationExamples:CountryCode must belong to an agreed, named Country Code list (+version)urn:oasis:names:tc:ciq:xNL:3:codelist:gc:Country-1 • Complex Rules ValidationExamples:- BirthDate < CurrentDate- StatusCode ‘Closed’ requires a ClosureReason.

24. UMCLVV Features, continued • Completely separate from W3C XML Schema • Platform-independent ISO/IEC 19757-3Schematron (implemented using W3C XSLT stylesheets) • Completely independent of Naming and Design Rules (NDRs) • Versioning in isolation of XML Schema

25. UMCLVV Process Overview OASIS UBL Methodology for Code List and Value Validation (UMCLVV) Data Exchange Partner Agreement Data Content Validation Requirements Validation Coding W3C XML Validation Stylesheet transform generate

26. UMCLVV involved Roles Documentation Developers & Testers Users OASIS UBL Methodology for Code List and Value Validation Data Content Validation Requirements Validation Coding W3C XML Validation Stylesheet transform generate Business Analysts & Testers Users (Developers) (Data Architects) Run-time Operator Specialist UMCLVV Service Staff

27. UMCLVV Run-Time Components W3C XML Document Schema(s) W3C XML Validation Stylesheet A A A 00101101 B XML file extends

28. Value Validation • The validation process involves the use of Schematron language and XSLTs • Schematron is a rule-based XML Schema language, developedby Rick Jelliffe and internationally standardized as ISO/IEC 19757-3, using XPath expressions to describe validation rules . • Schematron is used to confirm the success or failure of a set of assertions made about XML document instances. • Schematron can be used as an adjunct to DTDs, RelaxNG or XML Schemas. It allows co-occurrence constraints, non-regular constraints, and inter-document constraints

29. Methodology - Overview

30. Methodology Data Flow Diagram

31. W3C XML Document Schema W3C XML Validation Stylesheet A A A 00101101 B UMCLVV Status • OASIS draft standard 0.8 • Ownership of UMCLVV will move from UBL TC to CLR TC (will incorporate a name change) • No known platform-independent alternative • Plug-and-play run-time component • Methodology can evolve without impacting run-time requirements

32. References Customised Code List (gc) B C G H Application A UMCLVV Process Default Code List (gc) XML sch XSL A B C D E F Validated UMCLVV XSD References CVA structure validation Code list validation XML

33. Customised enterprise code lists Application A Business Rules Customised enterprise code lists Application B Business Rules Application of UMCLVV Process in an Enterprise Enterprise Code Lists UMCLVV Enterprise XML Schemas

34. Benefits of UMCLVV • Verify that instance document is valid as per DEPA • Validate data content platform-independently • Sender and receiver get the same validation result • Simple run-time requirement (XSLT) • Strong candidate to become a global industry standard(UN/CEFACT is taking an interest) • W3C Stylesheet and Schema are industry standards • Simple run-time requirement (XSLT or Pythonor any other ISO Schematron implementation)

35. Benefits of UMCLVV, continued • Supports versioned validation in isolation of schema version • Documentation is in synch with implementation • Validation can be switched on/off as required(by msg. server or appl.) • Simplifies application coding • Simple run-time requirement allows for evolution of UMCLVV • Details of methodology is transparent to operations

36. Risks of UMCLVV • An OASIS draft standard • UMCLVV not widely used yet • Methodology may change or evolve • Requires Schematron and XPath expertise • Affects the XML instance document processing (extra steps) • Affects the testing of XML Schema/XSLT release packages

37. OASIS CIQ TC Case Study – Using UMCLVV Methodology

38. OASIS CIQ Technical Committee • Industry Specifications for defining Party Centric Data from global (international) perspective • Party – Person or Organisation • Name (241+ countries in over 36 formats) • Address/Location (241+ countries in over 130 formats) • Party centric attributes • Party relationships Delivering royalty free, open, international, industry and application neutral XML specifications for representing, interoperating, and managing party (person/organization) centric information

39. Why Genericode and UMCLVV Approach for CIQ TC? • Keeps code list and values outside of the core CIQ XML Schemas • Provide users with the ability to define the semantics for the data represented in CIQ structure • Provide users with the ability to customize the CIQ XML Schemas without modifying the CIQ XML Schemas • Provides users the ability to write business rules to constrain the structure of the CIQ XML Schemas without modifying the XML schemas

40. OASIS CIQ Specifications • Party Name Schema – xNL.xsd • Supporting enumeration list (10) – xNL-types.xsd • Party Address Schema – xAL.xsd • Supporting enumeration list (30) – xAL-types.xsd • Party Information Schema – xPIL.xsd • Supporting enumeration list (56) –xPIL-types.xsd

41. CIQ Specifications without Genericode Approach

42. Use Party Name as Case Study

43. Code Lists defined in an XML Schema (xNL-types.xsd) that is “included” in xNL.xsd

44. Enumeration List referenced from xNL-types.xsd

45. xNL Enumeration List • Users given the choice to modify the code lists to meet their specific requirements • Basic default values provided, but it is up to the users to use them as is or customise it

46. xNL Enumeration List - Drawbacks • Each application has to have its own enumeration list • Point to point negotiations between applications • No standard enumeration list file that remains untouched • Change in enumeration list will result in change to application code generation • The Name schema might be used in multiple locations in an organisation (e.g. billing, marketing, sales, customer identification) and hence, customising the enumeration list is not straightforward • It might be an overhead for an application to use a large code list when it requires only 3 values

47. Objective of this case study • Move away from embedding code lists as XML schemas and “include” or “import” them in base XML schemas • Investigate the use of genericode approach and UMCLVV in CIQ Specifications • Implement genericode approach in CIQ Specifications as an optional feature • Customise the genericode based default code lists with specific requirements without modifying the default code lists • Apply business rule constraints on the core CIQ XML schemas without modifying the XML schemas

48. Case Study- Scenarios • Add a new code list value to default name code list (“NativePlaceName”) • Restrict the default name code list to allow no more than one first and last name (“FirstName”, “LastName”) • Restrict the default code list to allow only “FirstName”, “LastName”, and “NativePlaceName” as code values • Apply business rule constraints on XML Schema Customising the default xNL Code List without changing it to cater the above requirements is impossible

49. Preparing xNL Schema with Genericode Approach to Handle Code Lists

50. Step 1- Create default .gc files • Identify and decide on list-level and instance-level metadata to be included • Create .gc file for each enumeration list in xNL-types.xsd • Ensure that the .gc file is valid structurally against genericode-code-list.xsd file