[DDI-SRG] Reference Decision

[Wendy Thomas]

DECISION: Remove layered feature of all Reference elements and add 
attribute "isReference" with fixed value of true

EXAMPLE:
Currently
<VariableReference><r:Reference>

Change to
<VariableReference isReference="true">  type= r:Reference

Reasoning:
Reference is a very important structure within DDI. The current structure 
was done to facilitate XSLT with the use of a single reference element. 
The following arguments were presented to change to the structure 
described above:

. Add a layer of tagging in the structure

. This could be accomplished with a fixed attribute (a type aware query 
could find these without either layered or attribute)

. References are not the only construct of this type in DDI, but it is the 
only one treated this way (a point of consistency)

. Experience with layering has shown this to be an onerous structure

. If Reference is this way, we should be consistent in use of this 
structure with for example Identification

. An element with a single child is felt to be not necessary (simply not 
comfortable with it)

. What is the use case for finding all references of all types [validation 
processes]

. Don't have a strong use case at the moment for retaining

. Potential drawback of the filter is not so strong as we have no use 
case.



Wendy L. Thomas                          Phone: +1 612.624.4389
Data Access Core Director		 Fax:   +1 612.626.8375
Minnesota Population Center              Email: wlt at pop.umn.edu
University of Minnesota
50 Willey Hall
225 19th Avenue South
Minneapolis, MN 55455