- From: Karen Coyle <kcoyle@kcoyle.net>
- Date: Mon, 17 Oct 2016 08:42:24 -0700
- To: public-data-shapes-wg@w3.org
I should add that Dimitris and I went over the places where "validation" is used in the document, and noted where different meanings were being used. I think that Dimitris has a suggested to use "comparison" in some places where validation once was. (Although I also think he's traveling so we may have to wait for his thoughts.) If we use comparison for the act of comparing a data graph and a shapes graph, then the word "validate" can be eliminated. The next discussion is whether we want to use "valid" at all, and if there is a better term for a data graph that is consistent with the constraints of the shapes graph. kc On 10/17/16 12:06 PM, Irene Polikoff wrote: > I think the current definition doesn’t define “validation”. It defines > what it means for a data graph to be valid or to validate. > > The definition of the validation would need to start with something > like what Karen proposes e.g., validation is a process that determines > if a data graph validates against a shape graph. > > As for the the definition of what it means to be valid, it seems that > there are some possible holes: > > Are these conditions cumulative – meaning all need to be true or does > any single one is enough? > What does it mean for a node to validate against a shape? The first > bullets says what it means for a*focus node* to validate. The second one > says that each node must validate without mentioning the word focus. May > be it is a bit picky, but I felt there was some discontinuity. > > > Irene > > From: Holger Knublauch <holger@topquadrant.com > <mailto:holger@topquadrant.com>> > Date: Monday, October 17, 2016 at 1:44 AM > To: <public-data-shapes-wg@w3.org <mailto:public-data-shapes-wg@w3.org>> > Subject: Re: shapes-ISSUE-188 (define validation): "Validation" needs to > be defined > Resent-From: <public-data-shapes-wg@w3.org > <mailto:public-data-shapes-wg@w3.org>> > Resent-Date: Mon, 17 Oct 2016 05:45:02 +0000 > > Hi Karen, > > the current snapshot defines the term "validation" in the beginning of > section 3: > > The definition for validating a data graph <#dfn-data-graph> against > a shapes graph <#dfn-shapes-graph> as well as a node <#dfn-node> from > the data graph against a shape <#dfn-shape> from the shapes graph is > provided below: > > VALIDATION DEFINITION > > * A focus node <#dfn-focus-node> validates against a shape > <#dfn-shape> if and only if either it does not validate against > some filter <#dfn-filter> of the shape or none of the constraints > <#dfn-constraint> in the shape produce a validation result > <#dfn-validation-results> or a failure <#dfn-failure> for the focus > node. > * A data graph <#dfn-data-graph> validates against a shape > <#dfn-shape> if and only if each node that is in any of the targets > <#dfn-target> of the shape validates against the shape. > * A data graph <#dfn-data-graph> validates against a shapes graph > <#dfn-shapes-graph> if and only if the data graph validates against > eachshape <#dfn-shape> in the shapes graph. > > I believe this covers the terminology, esp with the different nuances of > validation, e.g. of a focus node. It also correctly identifies failures > as another possible outcome. > > Your proposal merely bases validation on another undefined term "obeys > the constraints", which IMHO just shifts the problem. The ultimate > definition may require an elaborated link to the evaluation mechanisms > including SPARQL queries, but Dimitris' prose above clarifies that > eventually it's about not producing any validation results and failures. > > What is missing for this ISSUE? > > Holger > > > On 9/10/2016 12:51, RDF Data Shapes Working Group Issue Tracker wrote: >> shapes-ISSUE-188 (define validation): "Validation" needs to be defined >> >> http://www.w3.org/2014/data-shapes/track/issues/188 >> >> Raised by: Karen Coyle >> On product: >> >> The term validation as used in SHACL needs to be defined. (The English language term is ambiguous.) The XML schema has a clear defiinition [1]. Based on that, I suggest the following as a definition of validation in SHACL: >> >> [Definition:] Validation is the process of determining whether a node in the data graph obeys the constraints expressed in a shapes graph. The validation result is true when the node in the data graph obeys the constraints, and false when it does not. >> >> Note that XML allows for 3 validation results: true, false, and undetermined. I do not know if SHACL also follows this pattern, so my true/false declaration above may need adjustment if that is the case. Here is what XML schema says: >> >> Note: As just defined, validation produces not a binary result, but a ternary one: if the information item is ·strictly assessed·, it will be either valid or invalid, but if no applicable declaration is found, its validity will be unknown (and its [validity] property will have the value notKnown). Whether in a particular application notKnown should be treated in the same way as invalid or differently is outside the scope of this specification; sometimes one choice is appropriate, sometimes the other. >> >> >> [1] See: https://www.w3.org/TR/2012/REC-xmlschema11-1-20120405/#key-vn > -- Karen Coyle kcoyle@kcoyle.net http://kcoyle.net m: 1-510-435-8234 skype: kcoylenet/+1-510-984-3600
Received on Monday, 17 October 2016 15:42:58 UTC