SHACL

Question 1

What is SHACL?

Answer 1

The W3C Shapes Constraint Language for defining and validating structural and value constraints on RDF graphs.

Question 2

Components of a SHACL NodeShape?

Answer 2

Shape name, targets (class/node/predicate-based), and property constraints.

Question 3

How to target all instances of a class?

Answer 3

Use sh:targetClass with the class IRI on a NodeShape.

Question 4

How to enforce exactly one property value?

Answer 4

In sh:property, set sh:minCount 1 and sh:maxCount 1 on the sh:path.

Question 5

How to enforce a property’s datatype?

Answer 5

Include sh:datatype with the appropriate XSD type in the property shape.

Question 6

How to restrict allowed values to a set?

Answer 6

Use sh:in with a list of permissible RDF terms.

Question 7

How to specify node kind (IRI, Literal)?

Answer 7

Use sh:nodeKind with sh:IRI, sh:Literal, or sh:BlankNode values.

Question 8

How to combine or negate shapes?

Answer 8

Use logical constraints sh:and, sh:or, and sh:not.

Question 9

How to limit unknown properties?

Answer 9

Set sh:closed true and list exceptions with sh:ignoredProperties.

Question 10

How are recursive shapes validated?

Answer 10

Through a fixpoint assignment process that ensures consistent node-shape mappings.