|modifications||inverses ReferenceToDocument definition||Changed from SET OF [0:1] IfcDocumentInformation FOR DocumentReferences to SET OF [0:?] IfcRelAssociatesDocument FOR RelatingDocument|
|modifications||inverses ReferenceToDocument name||Changed from ReferenceToDocument to DocumentRefForObjects|
An IfcDocumentReference is a reference to the location of a document. The reference is given by a system interpretable Location attribute (a URL string) where the document can be found, and an optional inherited internal reference Identification, which refers to a system interpretable position within the document. The optional inherited Name attribute is meant to have meaning for human readers. Optional document metadata can also be captured through reference to IfcDocumentInformation.
HISTORY New entity in IFC2.0
|1||Location||OPTIONAL IfcURIReference||Location, where the external source (classification, document or library) can be accessed by electronic means. The electronic location is provided as an URI, and would normally be given as an URL location string.|
> IFC4 CHANGE The data type has been changed from IfcLabel to IfcURIReference
|2||Identification||OPTIONAL IfcIdentifier||The Identification provides a unique identifier of the referenced item within the external source (classification, document or library). It may be provided as |
* a key, e.g. a classification notation, like NF2.3
* a handle
* a uuid or guid
It may be human readable (such as a key) or not (such as a handle or uuid) depending on the context of its usage (which has to be determined by local agreement).
> IFC4 CHANGE Attribute renamed from ItemReference for consistency.
|3||Name||OPTIONAL IfcLabel||Optional name to further specify the reference. It can provide a human readable identifier (which does not necessarily need to have a counterpart in the internal structure of the document).|
|ExternalReferenceForResources||SET [0:?] OF IfcExternalReferenceRelationship FOR RelatingReference||Reference to all associations between this external reference and objects within the IfcResourceObjectSelect that are tagged by the external reference.|
> IFC4 CHANGE New inverse attribute added with upward compatibility.
|4||Description||OPTIONAL IfcText||Description of the document reference for informational purposes.|
> IFC4 CHANGE New attribute added at the end of the attribute list.
|5||ReferencedDocument||OPTIONAL IfcDocumentInformation||The document that is referenced.|
|DocumentRefForObjects||SET [0:?] OF IfcRelAssociatesDocument FOR RelatingDocument||The document reference with which objects are associated.|
> IFC4 CHANGE New inverse attribute.
ENTITY IfcDocumentReference SUBTYPE OF (IfcExternalReference); Description : OPTIONAL IfcText; ReferencedDocument : OPTIONAL IfcDocumentInformation; INVERSE DocumentRefForObjects : SET [0:?] OF IfcRelAssociatesDocument FOR RelatingDocument; WHERE WR1 : EXISTS(Name) XOR EXISTS(ReferencedDocument); END_ENTITY;