Understanding the Example Model
- Every CDA template is represented as a UML class.
- In a CDA implementation guide, every class must be derived from a
subclass of the CDA base model
- The UML model containing all the different classes is the CDA base model
- There is a class for every complex type in the CDA schema.
- Every implementation guide needs to be specialized with a specific
- The purpose of the example UML is to illustrate the basic structures
that most every CDA implementation guide has.
- Notice that there are subclasses of classes
- Every implementation guide takes the CDA model and specializes it for a
particular type of clinical document.
- Template classes are often times reused
- A document also contains sections such as history of present illness,
past medical history, review of systems, etc. Each of these sections
might be where the physician would include the corresponding
- These domains are named ending with Section. For example: A History
& Physical contains at least one section which could be Past Medical
- This will be revisited again when we discuss re-using existing
- Keep in mind that CDA is the least restrictive model.
- Notice the "Open" headed arrow - denotes a "subclass of" and it denotes
which existing template it derives from.
- Every implementation guide has at least one template class derive from a
- Notice the "Solid" headed arrow denotes the UML association from one
class to another -i.e. the relationship between templates - contains -
representing a constraints.
- The multiplicity domain in the editor can describe the requirements for each
document and the conformance rules
- This domain provides information about how many sections the
document must contain
- The severity of the constraint is described with conformance rules
in one of the following ways: SHALL (required) contain, SHOULD
(suggested) contain or MAY (allowed) contain a specific section
- A problem is constrained for a particular purpose to make it easier
- The number in the multiplicity domain denotes the minimum and
maximum number of observations.
- In the case of 1.*, this denotes that there must be at least one but
that it can be multiple.