Enforce Existing Code-list Foreign Key Constraints

[canwaf]

Warn users if they try to assign a codelist but their dataset contains codes not in that codelist. Might not work for external codelists (or more work needed to get that to work), but if the codelist is held locally might be viable.

Local codelists to form part of MVP.

Could be via RDF representation of codelist, or from the codelist as a CSV.

Requires making request to PMD to check contents of code-list match what's in the local dataset (or alternatively specifying the local location for some ttl describing the existing code-list to allow the checks to be made).

We probably want to do this both in the python app - to provide some more helpful messages to the user, as well as adding the Foreign Key constraints into the CSV-W and letting csv-lint validate that they exist.

[robons]

todo: @robons to create a presentation for this.

[robons]

I don't think we're going to get around to doing this.