Definition
A Data Element is the logical definition of a unit of data such as:
a column in a database table
a field in a form
an element in an XML schema
Examples
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Date of birth
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Sex
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The definitions, including rules and constraints for valid values for all Data Elements are defined using the following metamodel:
Name: the name of the data element
Description: a description of the data class
Data type: this specifies the input value of the element e.g. varchar or datetime.
Metadata: any additional metadata associated with the data element
Cardinality: the number of times a data element can occur
Level: Could, Should, Must
Relationships: related data classes or elements (which may reside in another standard), including child/parent relationships
Example
How do data elements relate to other catalogue elements?
Data elements can be found contained within data classes. For example, the data class Participant might include the data elements: first name, surname, participant ID, date of birth, sex, etc.
Data Element values are constrained by Data Types. For example, the data element Date of birth may be associated with the data type xs:date, which only allows for the input of data in the YYYY-MM-DD format.