5.1.3.42 IfcRelationship

ABSTRACT This definition may not be instantiated

5.1.3.42.1 Semantic definition

IfcRelationship is the abstract generalization of all objectified relationships in IFC. Objectified relationships are the preferred way to handle relationships among objects. This allows to keep relationship specific properties directly at the relationship and opens the possibility to later handle relationship specific behavior.

There are two different types of relationships, 1-to-1 relationships and 1-to-many relationship. used within the subtypes of IfcRelationship. The following convention applies to all subtypes:

The two sides of the objectified relationship are named Relating+ and Related+
In case of the 1-to-many relationship, the related side of the relationship shall be an aggregate being a set 1:N

5.1.3.42.2 Entity inheritance

- IfcRoot

5.1.3.42.3 Attributes

#	Attribute	Type	Description
IfcRoot (4)
1	GlobalId	IfcGloballyUniqueId	Assignment of a globally unique identifier within the entire software world.
2	OwnerHistory	OPTIONAL IfcOwnerHistory	Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE only the last modification in stored - either as addition, deletion or modification. IFC4-CHANGE The attribute has been changed to be OPTIONAL.
3	Name	OPTIONAL IfcLabel	Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.
4	Description	OPTIONAL IfcText	Optional description, provided for exchanging informative comments.

Table 5.1.3.42.A

5.1.3.42.4 Concept usage

Concept	Usage	Description
IfcRoot (2)
Revision Control	General	Ownership, history, and merge state is captured using IfcOwnerHistory.
Software Identity	General	IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.
Click to show 2 hidden inherited concepts Click to hide 2 inherited concepts

Table 5.1.3.42.B

5.1.3.42.5 Formal representation

ENTITY IfcRelationship
 ABSTRACT SUPERTYPE OF (ONEOF
	(IfcRelAssigns
	,IfcRelAssociates
	,IfcRelConnects
	,IfcRelDeclares
	,IfcRelDecomposes
	,IfcRelDefines))
 SUBTYPE OF (IfcRoot);
END_ENTITY;