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.
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Data Element
IdentifierDefinitionNameValue DomainEtc.
Data Element
IdentifierDefinitionNameValue DomainEtc.
Data Element
IdentifierDefinitionNameValue DomainEtc.
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
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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
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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.
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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
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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
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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.
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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
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Naming Component Example
OBJECT CLASS TERM:Country
REPRESENTATION TERM:Name
PROPERTY TERM:Identifier
QUALIFIER TERMS:Trading partner
NAME:Trading partner country name
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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
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Recorded
Certified
Standardized
Retired
Incomplete
Registration Status
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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
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Metamodel Regions
Stewardship
Naming &Identification
Classification
Data ElementAdministration
Conceptual &Value DomainAdministration
Data ElementConcept
Administration
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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
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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
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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
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Value Domain Examples
• Geographic Codes
• Chemical Names
• Biological Classification
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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
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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
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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
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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
Conceptual Level:Object classand Property
Logical Level:Representation
with addition of qualifier,
Application Level
Representation class name
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
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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