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
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: the constraint on the data element e.g. integer, string
Cardinality: the number of times an lement can occur within a group
Level: Could, Should, Must
Metadata: any additional metadata associated with the data element
Relationships: related data classes or elements (which may reside in another standard), including child/parent relationships
Examples
Date of birth
Sex
Address
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.