In
metadata, a data element definition is a human readable phrase or sentence associated with a
data element
In metadata, the term data element is an atomic unit of data that has precise meaning or precise semantics. A data element has:
# An identification such as a data element name
# A clear data element definition
# One or more representation terms
...
within a
data dictionary
A data dictionary, or metadata repository, as defined in the ''IBM Dictionary of Computing'', is a "centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format". ''Oracle'' defines it ...
that describes the meaning or
semantics
Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference, meaning, or truth. The term can be used to refer to subfields of several distinct disciplines, including philosophy, linguistics and comp ...
of a data element.
Data element definitions are critical for external users of any data system. Good definitions can dramatically ease the process of mapping one set of data into another set of data. This is a core feature of
distributed computing
A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer sci ...
and intelligent agent development.
There are several guidelines that should be followed when creating high-quality data element definitions.
Properties of clear definitions
A good definition is:
# Precise - The definition should use words that have a precise meaning. Try to avoid words that have multiple meanings or multiple word senses. The definition should use the shortest description. The definition should not use the term you are trying to define in the definition itself. This is known as a circular definition.
# Distinct - The definition should differentiate a data element from other data elements. This process is called disambiguation - The definition should be free of embedded rationale, functional usage, legal metadata registration.
Definitions should not refer to terms or concepts that might be misinterpreted by others or that have different meanings based on the context of a situation. Definitions should not contain acronyms that are not clearly defined or linked to other precise definitions.
If one is creating a large number of data elements, all the definitions should be consistent with related concepts.
Critical Data Element – Not all data elements are of equal importance or value to an organization. A key metadata property of an element is categorizing the data as a Critical Data Element (CDE). This categorization provides focus for data governance and data quality. An organization often has various sub-categories of CDEs, based on use of the data. e.g.:
# Security Coverage – data elements that are categorized as personal health record.personal health information or PHI warrant particular attention for security and access
# Marketing Department Usage – The marketing department could have a particular set of CDEs identified for identifying Unique Customer or for Campaign Management.
# Finance Department Usage – The Finance department could have a different set of CDEs from Marketing. They are focused on data elements which provide measures and metrics for fiscal reporting.
Standards such as the ISO/IEC 11179 Metadata Registry specification give guidelines for creating precise data element definitions. Specifically chapter four of the ISO/IEC 11179 metadata registry standard.
Using precise words
Common words such as play or run database documents over 57 different distinct meanings for the word "play" but only a single definition for the term dramatic play. Fewer definitions in a chosen word's dictionary entry is preferable. This minimizes misinterpretation related to a reader's context and background. The process of finding a good meaning of a word is called Word sense disambiguation
Examples of definitions that could be improved
Here is the definition of "person" data element as defined in the www.w3c.org Friend of a Friend specificatio
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Person: A person.
Although most people do have an intuitive understanding of what a person is, the definition has much room for improvement. The first problem is that the definition is circular. Note that this definition really does not help most readers and needs to be clarified.
Here is the definition of the "Person" Data Element in the Global Justice XML Data Model 3.
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person: Describes inherent and frequently associated characteristics of a person.
Note that once again the definition is still circular. Person should not reference itself. The definition should use terms other than person to describe what a person is.
Here is a more precise but shorter definition of a person:
Person: An individual human being.
Note that it uses the word ''individual'' to state that this is an instance of a class of things called human being. Technically you might use "homo sapiens" in your definition, but more people are familiar with the term "human being" than "homo sapiens," so commonly used terms, if they are still precise, are always preferred.
Sometimes your system may have cultural norms and assumptions in the definitions. For example, if your "Person" data element tracked characters in a science fiction series that included aliens you may need a more general term other than ''human being''.
Person: An individual of a sentient species.
See also
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Data dictionary
A data dictionary, or metadata repository, as defined in the ''IBM Dictionary of Computing'', is a "centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format". ''Oracle'' defines it ...
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Data element
In metadata, the term data element is an atomic unit of data that has precise meaning or precise semantics. A data element has:
# An identification such as a data element name
# A clear data element definition
# One or more representation terms
...
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Global Justice XML Data Model
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NIEM
NIEM ( ) originated as an XML-based information exchange framework from the United States. NIEM also supports NIEM JSON exchanges. NIEM is currently developinthe NIEM Metamodel and Common Model Formatwhich can be expressed in any data serializati ...
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ISO/IEC 11179
The ISO/IEC 11179 Metadata Registry (MDR) standard is an international ISO/IEC standard for representing metadata for an organization in a metadata registry. It documents the standardization and registration of metadata to make data understandab ...
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Metadata
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Metadata registry
A metadata registry is a central location in an organization where metadata definitions are stored and maintained in a controlled method.
A metadata repository is the database where metadata is stored. The registry also adds relationships with r ...
References
{{Reflist
Sources
ISO/IEC 11179-4:2004 Metadata registries (MDR) - Part 4# ISO/IEC Technical Report 20943-1, First edition, 2003-08-01 Information technology — Procedures for achieving metadata registry consistency
ISO/IEC 11179
Metadata