metadata registry standards: a key to information integration

1

Metadata Registry Standards:

A Key to Information Integration

Jim CarpenterBureau of Labor Statistics

MIT SeminarJune 3, 1999

Previously presented to DAMA-NCR

by Judith Newton, NISTMay 11, 1999

see www.dama-ncr.org

2Agenda

•Specification and Standardization of Data Elements: ISO 11179, Parts 1-6

• Metamodel for Management of Shareable Data, ANS X3.285

• Specification of Data Value Domains, ISO TR 15452

• NWI for Content Issues

3

• Part1: Framework DIS

• Part2: Classification DIS

• Part 3: Basic Attributes IS

• Part 4: Formulation of Definitions IS

• Part 5: Naming and Identification IS

• Part 6: Registration IS

Parts of 11179

IS = International StandardDIS = Draft IS

Status

4

• Definitions

• Fundamental Concepts

• Other parts

• Informative Annexes

Part 1 - Framework

5

Definition: Data Element

A unit of data for which the • definition,

• identification,

• representation, and

• permissible values

are specified by means of a set of attributes.

6

Data Element

IdentifierDefinitionNameValue DomainEtc.

Data Element


Data Element


Database, File, Etc.

Record, Segment, Class, Tuple, Etc.

Field, Column, Etc.

Character, Image, Sound, Etc.

Database, File, Etc.

Transaction, Exchange Unit, Etc.

7

Fundamental Model

• Taken From Data Modeling

• 3 Components– object class

– property

– representation

8

Definition: Object Class

• Things for which to Store Data

• Entities in E-R Models

• Classes in O-O Models

• Examples:– Employers – Persons

– Automobiles – Orders

– ….

9

Definition: Property

• A peculiarity common to all members of an object class.

• Distinguishes or Describes Objects

• Attributes or Data Members in Models

• Examples:– Identifier – Age

– Address – Location

– ...

10

Definition: Representation

The combination of – a representation class,

– a value domain,

– a datatype,

– a unit of measure (if necessary)

– a character set (if necessary)

11

Data Element Example

Data Element

Flower

Color

String:{red | blue}

Object Class

Representation

Property

12

Part 2 - Classification

What forms can a classification structure take?• Keywords

• Controlled word lists

• Terms from models

• Thesaurus

• Taxonomy

• Ontology

– Acyclic directed graph, lattice

– Multiple inheritance

13

Each node in a classification structure is a taxon (plural: taxa).

• Given a classification structure, any taxa relating to a data element can be recorded

• The taxa can be recorded in a separate “classification” attribute

• With adequate software, users could access and navigate the classification structure

• A nonintelligent identifier for each taxon helps to deal with change

Classification -Fundamental Notions

14

Part 2 Status • ISO

– Draft International Standard

• Continuing R&D– Search engines

– Middleware - agents, mediators, request brokers

– XML tags

• New ISO project: terminology management in metadata registries

15

Part 3 - Basic Attributes

“Basic attributes” of data elements

•independent of their usage in application systems, data bases, data interchange messages.

•Recognizes need for additional attributes.

•No logical or physical structure of the data implied.

16

Categories of Basic Attributes

• Identification of a data element

• Definition of a data element

• Relations among data elements

• Representation of data element values

• Administrative: management and control

17Example Data ElementATTRIBUTENAME

EXAMPLE OBLIG

NameIdentifierVersionRegistration AuthoritySynonymous NameContext

Country code31661990ISO

MCCCOC

Definition code for country names M

Classification SchemeKeywordsRelated Data ReferenceType of Relationship

geopolitical entity, countryOOOC

Representation CategoryForm of RepresentationDatatype of DE valuesMax Size of DE valuesMin Size of DE valuesLayout of RepresentationPermissible DE values

character stringcodealphabetic character22

All 2-alpha codes in 3166

MMMMMCM

Responsible OrganizationRegistration StatusSubmitting OrganizationComments

ISO Maintenance AgencyStandard

OCOO

18

Summary• Part 3 is a good start to establishing an

unambiguous set of specifics documenting data elements.

• However,

– Further work on the other ISO 11179 parts and beyond has resulted in many refinements and advances addressing a variety of data-related concepts.

– A new work item involves replacing Part 3 with ANSI X3.285.

19

Part 4 - Data Definitions

A data definition shall:– Be unique (within a data dictionary)

– Be stated in the singular

– State what the concept is, rather than what it is not

– Be stated as a descriptive phrase or sentence(s)

– Contain only commonly understood abbreviations

– Be expressed without embedding definitions of other data elements or underlying concepts

20Data Definition Guidelines A data definition should:

• State the essential meaning of the concept

• Be precise and unambiguous

• Be concise

• Be able to stand alone

• Be expressed without embedding rationale, functional usage, domain information or procedural information

• Avoid circular reasoning

• Use consistent terminology and structure for related definitions

21

Part 5 - Naming and Identification

Five attributes to identify a data element

•Name

•Context

•Registration Authority Identifier

•Data Identifier

•Version Identifier

Always paired

InternationalRegistration Data Identifier

22

Principles for Registration of Data• Each data element has a unique identifier within

the register of a Registration Authority.

• A data element is uniquely identified by • Registration authority identifier• Data identifier• Version identifier

• To be assigned an identifier, the element must be derived, attributed, defined, named, and registered according to ISO/IEC 11179.

• A data element shall have at least one name within a context.

Combined

23

Naming Data Elements

• Naming principles are described in general terms with examples furnished.

• Rules are derived from the principles by which standard names are developed.

• These rules form a naming convention.• Because syntax, semantic and lexical rules vary by

organization, such as corporations or standards-setting bodies for business areas, no specific naming convention rules are prescribed in the International Standard.

• The naming principles described in the standard can be applied to other entities, such as attributes and objects.

24

Rule Types• Data element names are formed of components.

• The components are:

– object class terms

– property terms

– representation terms

– qualifier terms.

• Each is assigned meaning (semantics) and relative or absolute position (syntax) within a name.

• They are subject to lexical rules.

Counterparts in the X3.285 metamodel

25

Naming Component Example

OBJECT CLASS TERM:Country

REPRESENTATION TERM:Name

PROPERTY TERM:Identifier

QUALIFIER TERMS:Trading partner

NAME:Trading partner country name

26

Part 6 - RegistrationPart 6 - Registration

• Non exclusive registration: Every organization may be a Registration Authority.

• Data sharing registration: Data may be shared intra- or inter-organizationally.

• Economically enforced registration: Utility determines longevity and usefulness.

• Flexible Registration: Meta data may be registered at different levels of quality.

Meta Data Registration Principles

27

Recorded

Certified

Standardized

Retired

Incomplete

Registration Status

28

X3.285 - Metamodel

• Promote sharing of metadata for– understanding (meaning, representation, identification)– discovery– harmonization– reuse– analysis

• Provide a common base for metadata registries– management structure– components for interchange

29

Metamodel Regions

Stewardship

Naming &Identification

Classification

Data ElementAdministration

Conceptual &Value DomainAdministration

Data ElementConcept

Administration

30

DATA ELEMENT

Data Element Concept

Object Class

Property

Conceptual Domain

Value Meaning

PermissibleValues

Data ValueDomain

Representation Class

Data Element Representation

Data Element Model

31Data Element Model

Data Element

Data Element: A unit of data for which the definition, identification, representation, and permissible values are specified by means of a set of attributes.

Data Element Concept: An idea that can be represented in the form of a data element, described independently of any particular representation.

real world that can be identified

Object Class: A set of ideas, abstractions, or things in the

with explicit boundaries and meaning and whose properties and behavior follow the same rules.

Property: The human perception of a single characteristic of an object class in the real world. It has no particular associated means of representation by which the property can be communicated.

Data Element Representation: The part of a data element having a value domain, datatype,and other representational specifications.

Data ElementConcept

Object Class

Property

Data ElementRepresentation

32

Permissible Value

permissible value labelpermissible value begin datepermissible value end date

Representation ClassData Element Concept

Value Meaning

value meaning identifier (VMID)value meaning descriptorvalue meaning begin datevalue meaning end date

11

+represents

1

+means

1

Data Value Domain

value domain namevalue domain character set namevalue domain minimum character quantityvalue domain maximum character quantityvalue domain dependency descriptionvalue domain format

2..n

1

+contained in 2..n

+contains 1

enumerated value domain

0..*

1

Conceptual Domain

conceptual domain identifier

1

0..*

1

0..*

2..n

1

+contained in 2..n

+contains 1

enumerated conceptual domain

1..*1 1..*1

A

B

A contains B

ED0..*1 0..*1

a D may have any number of Esan E must have only one D

GF0..1 1..*0..1 1..*

a F must have one or more Gsa G may have zero or one F

KEY

Representation class name

33

Future Extensions & Work

• Promotion of X3.285 to an ISO standard

• Completion of TR 15452 - Data Value Domains

• XML Tags

• Content consistency

• Extended classification/terminology support

• Object extensions

34DTR 15452 -

Specification of Data Value Domains

• A set of permissible values.

• Types– Enumerated

• Countries of the world

– Non-Enumerated• All Real Numbers Between 0 & 1• 17 Char Alpha-Num• YYYYMMDD DTR = Draft Technical Report

Definition: Value Domain

35

Value Domain Examples

• Geographic Codes

• Chemical Names

• Biological Classification

36

The Problem

The sharing and reuse of data through equivalent data values will allow information to be exchanged faster and more efficiently.

Sets of reusable domain values, with unique identifiers assigned, eliminate the need for exact representation matches.

How can data values be mapped among representations so that the equivalent semantic meaning is determined, even if the language, format or character set of the representations differ?

The Benefits

37

Attributes for identification, specification, development and reuse of data value domains for data elements.

Assigning a unique identifier to each value within a domain.

Defining a data element conceptual domain and describing mappings between the values of a conceptual domain and the values of each representational data value domain.

Defining reuse of value domains among data elements.

Scope of the TR

38

Permissible Value



Value Meaning


11

+represents

1

+means

1

Data Value Domain


2..n

1

+contained in 2..n

+contains 1


0..*

1

Conceptual Domain


1

0..*

1

0..*

2..n

1

+contained in 2..n

+contains 1


1..*1 1..*1

A

B

A contains B

ED0..*1 0..*1

a D may have any number of Esan E must have only one D

GF0..1 1..*0..1 1..*

a F must have one or more Gsa G may have zero or one F

KEY


39

Permissible Value



Value Meaning


11

+represents

1

+means

1

Data Value Domain


2..n

1

+contained in 2..n

+contains 1


0..*

1

Conceptual Domain


1

0..*

1

0..*

2..n

1

+contained in 2..n

+contains 1


1..*1 1..*1

Conceptual Level:Object classand Property

Logical Level:Representation

with addition of qualifier,

Application Level


40Conceptual LevelObject Class

Name: CountryContext: ISO 3166Definition: All separate territories of the Earth.---------------------------------------------------------------------------------------------------------------------------------------Property

Name: IdentifierContext: <check ISO 1087>Definition: Means of distinguishing among objects.

---------------------------------------------------------------------------------------------------------------------------------------Data Element Concepts

Conceptual domain id: Country identifier Countryidentifier subset

Value meaningidentifier (VMID): 001-220 002

004005 . . .

Value meaning Identifiers for all Identifiers fordescription: the countries of the some of the

world. countries ofthe world.

V.m. date in: 19940101 19950603V.m. date out:

---------------------------------------------------------------------------------------------------------------------------------------Representation Class

Name: name codeContext: NIST SP 500-149 NIST SP 500-149Definition: A designation for an object. A system of valid symbols

which substitute for longer values.------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

41------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Logical Level Application Level

Logical Data Element Application Data Element(Generic Data Element)(Reference Data Element)

Name: Country name Trading partner country codeContext: ANSI/ISO/NISO fictionalIRDI: 3166 4488Definition: The names of all the A subset of

countries of the world. 3166,selected by trading treaty.

------------------------------------------------------------------Data concept attributes Note: In a registry implementation, the listing of these attributes could be replaced by a link to the DEC.

Conceptual domain id: Country identifier Countryidentifier subset

Value meaningidentifier (VMID): 001-220 002

004005 . . .

Value meaning Identifiers for all Identifiers fordescription: the countries of the some of the

world. countries ofthe world.

V.m. date in: 19940101 19950603V.m. date out:------------------------------------------------------------------Data element representation attributes

Value domain name: short name in English 2-alpha codeRep. class name: name codeV.d. character set name: alphabetic character numeric

characterV.d.min. char. quantity: 4 2V.d.max. char. quantity: 40 2Permissible value label: All names of countries some 2-alpha

in short English form codes forlisted in ISO 3166 countries

listed in ISO 3166, modifiedas described intrade treaty xx.

P.v. date in: 19940101 19950603P.v. date out:V.d. dependency desc: none This value domain is a subset of ISO 3166.V.d. format: text AA

42

Conclusion

Application of all principles of the ISO 11179 family to the development of meta data registries allows easy and effective exchange of data and meta data nationally and internationally.

43References

Applicable Documents, all available at:ftp://www.sdct.itl.nist.gov/L8

ISO/IEC 11179, Specification and Standardization of Data Elements

Part 1: Framework for the Specification and Standardization of Data Elements Part 2: Classification for Data ElementsPart 3: Basic Attributes of Data ElementsPart 4: Rules and Guidelines for the Formulation of Data DefinitionsPart 5: Naming and Identification Principles for Data ElementsPart 6: Registration of Data Elements

ANS X3.285, Metamodel for the Management of Sharable Data

ISO DTR 15452, Specification of Data Value Domains

Web enabled Registries:

National Health Information Knowledgebase (NHIK) from Australian Institute of Health andWelfare (AIHM)http://www.aihw.gov.au

Environmental Data Registry (EDR) from the U.S. Environmental Protection Agency (EPA)http://www.epa.gov/edr