What is profiling?

Profiling is the act of creating a "profile" of something.

Generically, in English, a "profile" of something is as follows:

The outline of a physical object or feature, or a representation of this

- Oxford English dictionary, use of the word "profile" since the 17th century

Within the world of data, a derived definition of "profile" consistent with the above is —

A summary or an extraction

In this definition, the essence of the English word is retained, since a summary or extraction of or from a data object may be an outline of it; for example, a 2D representation of a 3D spatial object. or a statistical summary of a dataset having lots of parts.

By definition, SHACL constrains (RDF) data. Therefore, any data that is valid according to a shapes graph will be a profile of the data graph that was validated. If a shapes graph validates all elements of a data graph, the resulting valid data will be a "null" profile of the data graph, meaning it is identical to the original data graph.

The W3C's Profiles Vocabulary [[dx-prof]] has defined "data profiling" in the context of specifications or data specifications:

A data specification that constrains, extends, combines, or provides guidance or explanation about the use of other data specifications.

If a shapes graph is taken to be a "data specification," then not only is the data that is valid according to the shapes graph a profile of the validated data graph, but the shapes graph itself also serves as a profile of the data model used for the data graph.

Scope

With the above section's concepts in mind, this specification defines the following:

1. profiles of SHACL
2. profiling with SHACL

Terminology

Terminology used throughout this specification is taken from several sources:

SHACL 1.2 Core specification

technical terms for SHACL and RDF, the latter from [[rdf12-concepts]]

Profiles Vocabulary [[dx-prof]]

defines general terms to do with profiling including the terms "profiling" & "profile"

The SHACL & RDF terms include: binding , blank node , conformance , constraint , constraint component , data graph , datatype , failure , focus node , RDF graph , ill-formed , IRI , literal , local name , member , node , node shape , object , parameter , pre-binding , predicate , property path , property shape , RDF term , SHACL instance , SHACL list , SHACL subclass , shape , shapes graph , solution , subject , target , triple , validation , validation report , validation result , validator , value , value node .

The general profiling terms include: specification , [data] profile , metadata .

Document Conventions

Within this specification, the following namespace prefix definitions are used:

Within this specification, the following JSON-LD context is used:

{
  "@context": {
    "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
    "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
    "sh": "http://www.w3.org/ns/shacl#",
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "ex": "http://example.com/ns#"
  }
}

Note that the URI of the graph defining the SHACL vocabulary itself is equivalent to the namespace above, i.e., it includes the #. References to the SHACL vocabulary, e.g., via owl:imports should include the #.

Throughout the specification, color-coded boxes containing RDF graphs in Turtle and JSON-LD will appear. The color and title of a box indicate whether it is a Shapes graph, a Data graph, or something else. The Turtle specification fragments use the prefix bindings given above. The JSON-LD specification fragments use the context given above. Only the Turtle specifications will have parts highlighted.

// This box represents an input shapes graph

{
  "@id": "ex:s",
  "ex:p": {
    "@id": "ex:o"
  }
}

// This box represents an input data graph

{
	"@graph": [
		{
			"@id": "ex:Alice",
			"@type": "ex:Person"
		},
		{
			"@id": "ex:Bob",
			"@type": "ex:Person"
		}
	]
}

// This box represents an output results graph

Grey boxes such as this include syntax rules that apply to the shapes graph.

true denotes the RDF term "true"^^xsd:boolean. false denotes the RDF term "false"^^xsd:boolean.

TODO