The element control is an expression of the ELEMENT class of the openEHR reference model and is the leaf node expression of any openEHR information (UML). Its key features are discussed individually.
Requirements
- The name of the element must if allowed in the archetype, to be set at run time
- The element must allow itself to be replicated and renamed if allowed in the archetype
- The element must allow a Null Flavor to be added from the appropriate value domain if no value is given
- The element must display that it is required but does not validate in an appropriate manner when validation is called
Features
The features of an Element control that provides the basic functionality for openEHR implementation is described below.
Name
(from Locatable)
Each element has a name which gives information about its meaning to the user. At the level of the archetype the name has an associated description of what it is and bindings to terms in terminologies which may be provided as further information to the user at the level of the application. The name and this description are language dependent. Although all languages could be expressed within the widget it is thought appropriate at this point to limit the expression in any particular environment to one language and not have language handling at the level of the widget.
Value
The value is a data value type and is expressed as a data value widget. A value is required unless a Null flavor is set.
Null flavor
A null flavor is a textural value (DV_CODED_TEXT) from an openEHR value set which expresses the reason why the value is omitted. This would usually only be present if the ELEMENT was mandatory and had to be present. The default behaviour of openEHR is to omit data points that are not mandatory and not populated.
Add another instance
A button or menu item must be available if the occurrences of an element have an upper limit greater than 1 which allows the Element to be duplicated. The new instance will get an automatic name but must be able to be renamed as per the constraints set in the archetype.