- From: Luc Moreau <l.moreau@ecs.soton.ac.uk>
- Date: Sun, 30 Oct 2011 17:54:37 +0000
- To: W3C provenance WG <public-prov-wg@w3.org>
In the interest of simplification, we would like to make the following proposal about attributes in prov-dm. Proposal 1: attributes are a necessary part of prov-dm. Attribute-value pairs can be optionally included in Entity Expressions and Activity Expressions. The document will justify their presence along the following lines (text to be worked on, suggestions welcome). For inter-operability purpose, it is necessary to be able to describe entities (and activities), and such descriptions need to be part of the provenance record, so that queries over such descriptions can be expressed. The document will not make the distinction between non-characterizing and characterizing attributes. All attributes will be considered as describing some facet of the entity. Proposal 2: Constraints related to attributes will be dropped. http://www.w3.org/TR/2011/WD-prov-dm-20111018/#derivation-attributes http://www.w3.org/TR/2011/WD-prov-dm-20111018/#use-attributes http://www.w3.org/TR/2011/WD-prov-dm-20111018/#generation-affects-attributes Rationale: a number of issues have been raised against these constraints. They may or may be fixable. But overall, they seem to overconstraint the model, for benefits that are unclear. There was no intent to make them automatically verifiable, for instance. Furthermore, if it is really crucial for some developers to express that some attributes depend on others, than prov-dm already offers a mechanism: simply model these attributes as entities, and their dependency as derivation. A further consequence is that derivation can be made transitive! (subject of a separate proposal) Finally, the semantics team may want to reconsider these constraints and formalize them properly. Cheers, Luc
Received on Sunday, 30 October 2011 17:56:24 UTC