> For the complete documentation index, see [llms.txt](https://gitbook.semantify.it/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook.semantify.it/domainspecifications/ds-v7/grammar/domainspecification/class.md). # Class Node A Class Node is used as a potential range for a [Property Node](/domainspecifications/ds-v7/grammar/domainspecification/property.md). It is represented by an object with `"@type": "sh:NodeShape"` that is wrapped by the term `sh:node`. This NodeShape is used to express all the characteristics and constraints of the Class Node. The most important constraint is `sh:class`, which constraints the class(es) that the target entity must have. For `sh:class` arrays are allowed, which are supposed to represent multi-typed entities (MTE). The `@id` of a Class Node is used to reference it in other parts of the Domain Specification, and so reuse already defined constraints for a specific Class. Details below. ## 1. Example ```json { "sh:node": { "@id": "https://semantify.it/ds/OBbzsh4_B#DpruH", "@type": "sh:NodeShape", "sh:class": [ "schema:Airport" ], "rdfs:label": [ { "@language": "en", "@value": "Airport" }, { "@language": "de", "@value": "Flughafen" } ], "rdfs:comment": [ { "@language": "en", "@value": "An international Airport that is identified by its ICAO identifier." } ], "sh:closed": true, "ds:propertyDisplayOrder": [ "schema:name", "schema:icaoCode", "schema:url" ], "sh:property": [ ... ] } } ``` ## 2. Key-value Table The following table lists all possible terms that can be used by a Class Node. The order in the table reflects the recommended order of these terms within a Class Node (optional). | key | required | value type | description | related error | | :-----------------------: | :------: | :------------------------------: | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------------------------------: | | `@id` | true | *IRI* | The IRI of the Class Node, which is based on the DS IRI it is in | | | `@type` | true | `"sh:NodeShape"` | The fixed type for a Class Node | | | `sh:class` | true | \[ *IRI* ] | The IRI(s) of the Class(es) that the entity must have | Non-conform range | | `rdfs:label` | false | List of *Language tagged String* | The label for this Class | | | `rdfs:comment` | false | List of *Language tagged String* | The description for this Class | | | `sh:closed` | false | *Boolean* | Specifies if additional properties are allowed or not | Non-conform property | | `ds:propertyDisplayOrder` | false | List of **IRI** | A list of property IRIs that reflect the order of the properties for this Class. If this property is used, it replaces the order given by `sh:order` of the property nodes in question. | | | `sh:property` | false | List of **PropertyNode** | A list of property nodes that apply to the entity | Missing Property, Non-conform Property | ## 3. Semantics ### 3.1. Class-Matching See [SHACL specification](https://www.w3.org/TR/shacl/#ClassConstraintComponent). A Class Node includes `sh:class` to specify the class(es) that the verified entity **MUST** match. Domain Specifications use [custom semantics for class matching](/domainspecifications/ds-v7/grammar/verificationreport/ds-verification.md). Examples: ``` "sh:class": [ "schema:LodgingBusiness", "schema:Restaurant" ] ``` ``` "sh:class": [ "schema:Article" ] ``` ### 3.2. Properties The terms `sh:property` and `sh:closed` are used in a Class Node to give further restrictions on the properties of the corresponding entity. Such a Class Node with property restrictions is also called **Restricted Class Node**. A Class Node without further property restrictions is called a **Standard Class Node**. #### 3.2.1. sh:property See [SHACL specification](https://www.w3.org/TR/shacl/#PropertyConstraintComponent). The term `sh:property` lists the property shapes that the target entity must comply with. For every property, there is a corresponding [Property Node](/domainspecifications/ds-v7/grammar/domainspecification/property.md) in this list. Example: ```json "sh:property": [ { "@type": "sh:PropertyShape", "sh:order": 0, "sh:path": "schema:identifier" "sh:maxCount": 1, "sh:or": [ { "sh:datatype": "xsd:string", } ] }, { "@type": "sh:PropertyShape", "sh:order": 1, "sh:path": "schema:alternateName" "sh:maxCount": 1, "sh:or": [ { "sh:datatype": "xsd:string", } ] } ] ``` #### 3.2.2. sh:closed See [SHACL specification](https://www.w3.org/TR/shacl/#ClosedConstraintComponent). The term `sh:closed` can be used to specify if additional properties (other than the properties allowed by `sh:property`) are allowed or not. In the past, Domain Specifications had `"sh:closed": true` implicitly in all NodeShapes. Now the DS creator should specify the wished behaviour. Example: ```json "sh:closed": true ``` #### 3.2.3. ds:propertyDisplayOrder The term `ds:propertyDisplayOrder` provides a list of property IRIs that reflect a wished order of the properties for display purposes. Details about this term can be found in [DomainSpecification.md](/domainspecifications/ds-v7/grammar/domainspecification/domainspecification.md). ### 3.3. Metadata Following terms represent metadata about the given class. These terms do not have any effects on the verification result; They have only informational character. #### 3.3.1. rdfs:label The term `rdfs:label` CAN be used to give the class a label (in different languages). The value for this term is a language-tagged string. The standard label for a class term is usually provided by its vocabulary itself, `rdfs:label` can be used to overwrite that standard label or provide a single label for multi-class entities (a class that has multiple `sh:class` entries). Example: ``` { "@id": "https://semantify.it/ds/OBbzsh4_B#DpruH", "@type": "sh:NodeShape", "sh:class": [ "schema:LodgingBusiness", "schema:Restaurant" ], "rdfs:label": [ { "@language": "en", "@value":"Hotel and Restaurant" } ], ... } ``` #### 3.3.2. rdfs:comment The term `rdfs:comment` CAN be used to describe the class (in different languages). The value for this term is a language-tagged string. The standard description for a class term is usually provided by its vocabulary itself, `rdfs:comment` can be used to overwrite that standard description or provide a single description for multi-class entities (a class that has multiple `sh:class` entries). Example: ``` { "@id": "https://semantify.it/ds/OBbzsh4_B#DpruH", "@type": "sh:NodeShape", "sh:class": [ "schema:LodgingBusiness", "schema:Restaurant" ], "rdfs:comment": [ { "@language": "en", "@value":"A business that offers rooms and has a restaurant in the same building." } ], ... } ```