Basic Package

One of the most basic types of data is boolean or bi-state data. The need here is for a type which both includes a boolean value, and which inherits from the type DATA_VALUE, enabling it to be used as an ELEMENT.value.

A type is required to represent state values of a state machine. In a simple system of data types, a simple integer would appear sufficient to perform this job. However, in an archetyped framework, a distinct type is required, so that it can be archetyped not by the constraints used for integers, but by a state machine definition instead. The type DV_STATE is provided for this purpose. An example of a state machine which models the lifecycle of a medication order is illustrated in the figure below. This definition would appear in an archetype; the values of a DV_STATE object are then restricted to the values of the states in the definition.

Real world entities (RWEs) such as people, car engines, invoices, and appointments may all be assigned identifiers. Although many of these are designed to be unique within a jurisdiction or issuing space, they are often not, due to data entry errors, bad design (ids which are too small or incorporate some non-unique characteristic of the identified entities), bad process (e.g. non-synchronised id issuing points); identity theft (e.g. via theft of documents of proof or hacking). In general, while some real world identifiers (RWIs) are 'nearly unique', none can be guaranteed so. Therefore, from a strict computatoinal point of view, RWIs are not treated as reliable identifiers, but as attributes of their owning objects, in the same ways as names and addresses for example.

Examples of RWE identifiers which are intended to be unique within the space of the issuing authority or organisation include:

The defining logical characteristic of RWE ids is that they continue to identify the entities in question, regardless of how they change in time; for example a social security number does not change when someone changes their hair colour or even their gender (both of which attributes may be recorded in the database). In general it should be the case that if two RWE ids are equal, they refer to the same RWE.

At a practical level, RWE identifiers differ from information entity (IE) identifiers in that the former are generally not assigned by the computing infrastructure that uses them - that is to say, in the production computing system, such identifiers are no different from other characteristics of the entity, such as names or addresses.