Data element name
Encyclopedia
A data element name is a name given to a data element
in, for example, a data dictionary
or metadata registry
. In a formal data dictionary, there is often a requirement that no two data elements may have the same name, to allow the data element name to become an identifier, though some data dictionaries may provide ways to qualify the name in some way, for example by the application system or other context in which it occurs.
In a database driven data dictionary, the fully qualified data element name may become the primary key, or an alternate key, of a Data Elements table of the data dictionary.
The data element name typically conforms to ISO/IEC 11179
metadata registry
naming conventions and has at least three parts:
Many standards require the use of Upper camel case to differentiate the components of a data element name. This is the standard used by ebXML
, GJXDM
and NIEM.
Tables are Collections of Entities, and follow Collection naming guidelines. Ideally, a collective name is used: e.g., Personnel. Plural is also correct: Employees. Incorrect names include:
Employee, tblEmployee, and EmployeeTable.
Columns are Properties of the Entity and are named in a multi-part format:
[Object] [Qualifier] Property RepresentationTerm
The Object part may be omitted from a name when the property is within its object's context. The Qualifier is used when it is necessary to uniquely identify an element. For example, columns on the WorkOrders table would be expressed as:
WorkOrder_Number
Requirements_Text
Requesting_Employee_Number
Approving_Employee_Number
For Requirements_Text, the full name (i.e., the name that goes in the registry, or data dictionary) is WorkOrder_Requirements_Text; the Object part is omitted because it is declared in the WorkOrders table.
The Requesting_Employee_Number and Approving_Employee_Number columns have Qualifiers to ensure that the data element names are unique and descriptive. The Object part of the element name is also omitted because it is declared within the object context.
Note that for the examples provided, an underscore was used as a separator. A separator is not mandated by ISO/IEC 11179 but is recommended.
Data Element names that have a multi-part Camel Case format:
Object [Qualifier] Property RepresentationTerm
The specification also includes normative documentation in appendices.
For example the XML element for a person's given (first) name would be expressed as:
John
Where Person is the Object=Person, Property=Given and Representation term
="Name". In this case the optional qualifier is not used.
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...
in, for example, a data dictionary
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." The term may have one of several closely related meanings pertaining to...
or metadata registry
Metadata registry
A metadata registry is a central location in an organization where metadata definitions are stored and maintained in a controlled method.-Use of Metadata Registries:...
. In a formal data dictionary, there is often a requirement that no two data elements may have the same name, to allow the data element name to become an identifier, though some data dictionaries may provide ways to qualify the name in some way, for example by the application system or other context in which it occurs.
In a database driven data dictionary, the fully qualified data element name may become the primary key, or an alternate key, of a Data Elements table of the data dictionary.
The data element name typically conforms to ISO/IEC 11179
ISO/IEC 11179
ISO/IEC 11179 is an international standard for representing metadata for an organization in a metadata registry.- Intended purpose :...
metadata registry
Metadata registry
A metadata registry is a central location in an organization where metadata definitions are stored and maintained in a controlled method.-Use of Metadata Registries:...
naming conventions and has at least three parts:
- Object, Property and Representation termRepresentation termA representation term is a word, or a combination of words, that semantically represent the data type of a data element. A representation term is commonly referred to as a class word by those familiar with data dictionaries...
.
Many standards require the use of Upper camel case to differentiate the components of a data element name. This is the standard used by ebXML
EbXML
Electronic Business using eXtensible Markup Language, commonly known as e-business XML, or ebXML as it is typically referred to, is a family of XML based standards sponsored by OASIS and UN/CEFACT whose mission is to provide an open, XML-based infrastructure that enables the global use of...
, GJXDM
GJXDM
The Global Justice XML Data Model is a data reference model for the exchange of information within the justice and public safety communities...
and NIEM.
Example of ISO/IEC 11179 naming in relational databases
ISO/IEC 11179 is applicable when naming tables and columns within a relational database.Tables are Collections of Entities, and follow Collection naming guidelines. Ideally, a collective name is used: e.g., Personnel. Plural is also correct: Employees. Incorrect names include:
Employee, tblEmployee, and EmployeeTable.
Columns are Properties of the Entity and are named in a multi-part format:
[Object] [Qualifier] Property RepresentationTerm
The Object part may be omitted from a name when the property is within its object's context. The Qualifier is used when it is necessary to uniquely identify an element. For example, columns on the WorkOrders table would be expressed as:
WorkOrder_Number
Requirements_Text
Requesting_Employee_Number
Approving_Employee_Number
For Requirements_Text, the full name (i.e., the name that goes in the registry, or data dictionary) is WorkOrder_Requirements_Text; the Object part is omitted because it is declared in the WorkOrders table.
- Object is omitted in full name.
- Property is WorkOrder in full name?
- RepresentationTerm is Requirements_Text in full name?
The Requesting_Employee_Number and Approving_Employee_Number columns have Qualifiers to ensure that the data element names are unique and descriptive. The Object part of the element name is also omitted because it is declared within the object context.
Note that for the examples provided, an underscore was used as a separator. A separator is not mandated by ISO/IEC 11179 but is recommended.
Example of ISO/IEC 11179 name in XML
Users frequently encounter ISO/IEC 11179 when they are exposed to XMLXML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
Data Element names that have a multi-part Camel Case format:
Object [Qualifier] Property RepresentationTerm
The specification also includes normative documentation in appendices.
For example the XML element for a person's given (first) name would be expressed as:
Where Person is the Object=Person, Property=Given and Representation term
Representation term
A representation term is a word, or a combination of words, that semantically represent the data type of a data element. A representation term is commonly referred to as a class word by those familiar with data dictionaries...
="Name". In this case the optional qualifier is not used.
See also
- Data dictionaryData dictionaryA 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." The term may have one of several closely related meanings pertaining to...
- Data elementData elementIn 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...
- Data element definitionData element definitionIn metadata, a data element definition is a human readable phrase or sentence associated with a data element within a data dictionary that describes the meaning or semantics of a data element....
- ISO/IEC 11179ISO/IEC 11179ISO/IEC 11179 is an international standard for representing metadata for an organization in a metadata registry.- Intended purpose :...
- Representation termRepresentation termA representation term is a word, or a combination of words, that semantically represent the data type of a data element. A representation term is commonly referred to as a class word by those familiar with data dictionaries...
- Semantic spectrumSemantic spectrumThe semantic spectrum is a series of increasingly precise or rather semantically expressive definitions for data elements in knowledge representations, especially for machine use.At the low end of the spectrum is a simple binding of a single word or phrase and its...