What is a Data Element?

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:

1. Name: the name of the data element

2. Description: a description of the data class

3. Data type: this specifies the input value of the element e.g. varchar or datetime.

4. Metadata: any additional metadata associated with the data element

5. Cardinality: the number of times a data element can occur

6. Level: Could, Should, Must

7. Relationships: related data classes or elements (which may reside in another standard), including child/parent relationships

Example

 

Open

Open

 

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.

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