IfcDatasetReference

Item	SPF	XML	Change	Description
IFC4X3_ADD2 to IFC4X4_draft
IfcDatasetReference			ADDED

Semantic definitions at the entity

Entity definition

An IfcDatasetReference is a reference to the location of a dataset. 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 dataset. The optional inherited Name attribute is meant to have meaning for human readers. Optional dataset metadata can also be captured through reference to IfcDatasetInformation. Furthermore, the optional Filter attribute can be used to provide a text as e.g. SQL, XQuery etc to filter out data when only a subset is relevant for the dataset reference.

Attribute definitions

#	Attribute	Type	Cardinality	Description	G
4	Description	IfcText	?	Description of the dataset reference for informational purposes.	X
5	ReferencedDataset	IfcDatasetInformation	?	Information about the referenced dataset.	X
6	Filter	IfcText	?	An optional text as e.g. SQL, XQuery etc to filter out data when only a subset is relevant for the dataset reference.	X
	DatasetRefForObjects	IfcRelAssociatesDataset @RelatingDataset	S[0:?]	The dataset reference with which objects are associated.	X

Formal Propositions

Rule	Description
WR1	A name should only be given, if no dataset information (including the dataset name) is attached.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	G
IfcExternalReference
1	Location	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 .	X
2	Identification	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.	X
3	Name	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).	X
	ExternalReferenceForResources	IfcExternalReferenceRelationship @RelatingReference	S[0:?]	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.	X
IfcDatasetReference
4	Description	IfcText	?	Description of the dataset reference for informational purposes.	X
5	ReferencedDataset	IfcDatasetInformation	?	Information about the referenced dataset.	X
6	Filter	IfcText	?	An optional text as e.g. SQL, XQuery etc to filter out data when only a subset is relevant for the dataset reference.	X
	DatasetRefForObjects	IfcRelAssociatesDataset @RelatingDataset	S[0:?]	The dataset reference with which objects are associated.	X

Formal representations

XML Specification

 <xs:element name="IfcDatasetReference" type="ifc:IfcDatasetReference" substitutionGroup="ifc:IfcExternalReference" nillable="true"/>

 <xs:complexType name="IfcDatasetReference">

  <xs:complexContent>

   <xs:extension base="ifc:IfcExternalReference">

    <xs:sequence>

     <xs:element name="ReferencedDataset" type="ifc:IfcDatasetInformation" nillable="true" minOccurs="0"/>

    </xs:sequence>

    <xs:attribute name="Description" type="ifc:IfcText" use="optional"/>

    <xs:attribute name="Filter" type="ifc:IfcText" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcDatasetReference

 SUBTYPE OF (IfcExternalReference);

  Description : OPTIONAL IfcText;

  ReferencedDataset : OPTIONAL IfcDatasetInformation;

  Filter : OPTIONAL IfcText;

 INVERSE

  DatasetRefForObjects : SET [0:?] OF IfcRelAssociatesDataset FOR RelatingDataset;

 WHERE

  WR1 : EXISTS(Name) XOR EXISTS(ReferencedDataset);
END_ENTITY;

 EXPRESS-G diagram