DDS Structure

[mikemolter]

How close, if at all, do we want the DDS structure to follow the define-xml structure? For example, do we want to continue the approach of defining things once and referencing them as often as needed? Do we define items once, and then common items such as STUDYID can be referenced from multiple itemgroupdefs? In JSON this translates to item attributes within itemgroups that are not inlined, so define-xml itemrefs translate to a list of OIDs for the items attribute. If so, what do we do with something like method references? Keep in mind that in define.xml, a method is referenced, not from the itemdef (like codelists and valuelists), but from the itemref. In other words, a method is not a defining attribute of an item. How does this translate to json, which allows for non-inlined OID references, but there's no room for method references?

On the other hand, if we insist on everything being inlined, then we have to re-define STUDYID every time we use it. This can get messy for items that then reference codelists.

Or is there a middle ground?

[mikemolter]

If we do want to stay closer to the classic define.xml model, then a model like the following would allow references to items definitions from within itemgroups, and still have attributes to that reference, as we currently do with ItemRef elements:

classes:

ItemRef:
attributes:

  item:
    range: Item
    inlined: false
  OrderNumber:
    range: integer

  Mandatory:
    range: Boolean
     required: true

  KeySequence:
     range: integer

  method:
     range: Method
     inlined: false

ItemGroup:
attributes:

  items:
    range: ItemRef
    multivalued: true
    inlined: true
    inlined_as_list: true
 <other-attributes>

The JSON would look something like this (illustrated only with the items attribute):

{

"itemGroups": [
{
"items": [
{
"item": "IT.STUDYID",
"OrderNumber": 1,
"KeySequence":1,
"Mandatory": true
},
{
"item": "IT.DOMAIN",
"OrderNumber": 2,
"Mandatory": true
}
]
}
]
}

[swhume]

In general, we do not need to follow the Define-XML model, but we do want to generate a Define-XML from the DDS. If there's a better way to do things, for example, getting rid of the Def/Ref, then we should consider it.