Mandatory elements in archetypes, and user interfaces

Thomas Beale thomas.beale at
Fri Nov 10 08:27:20 EST 2017

On 10/11/2017 11:21, Boštjan Lah wrote:
>> On 10 Nov 2017, at 14:19, Thomas Beale <thomas.beale at> wrote:
>> you can't restrict from 1..1 => 0..* in a template - it's not allowed in any restriction algebra, of which ADL is an example.
>> If it is thought that no occurrnces constraint might be needed in any derivative archetype or template, the original parent should have 0..1 or 0..* as appropriate.
> Yes, but I think making all archetypes generic like Gerard suggests is not a good idea.

I agree. Where there is a focal element that can't be null (in the 
programming sense) it should be 1..1 or 1..*; that's part of the 
semantic definition. Archetypes are about data; what goes on in the 
screen is more complicated sometimes. Particularly with pre-filled 
and/or defaulted fields.

- thomas

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