IfcPropertyEnumeration is a collection of simple or measure values that define a prescribed set of alternatives from which 'enumeration values' are selected. This enables inclusion of enumeration values in property sets. IfcPropertyEnumeration provides a name for the enumeration as well as a list of unique (numeric or descriptive) values (that may have a measure type assigned). The entity defines the list of potential enumerators to be exchanged together (or separately) with properties of type IfcPropertyEnumeratedValue that selects their actual property values from this enumeration.
The unit is handled by the Unit attribute, see Table 184.108.40.206.A for an example of a unitless property enumeration:
- If the Unit attribute is not given, than the unit is already implied by the type of IfcMeasureValue or IfcDerivedMeasureValue. The associated unit can be found at the IfcUnitAssignment globally defined at the project level (IfcProject.UnitsInContext).
- If the Unit attribute is given, the unit assigned by the unit attribute overrides the globally assigned unit.
|Name||EnumerationValues||Type (through IfcValue)||Unit|
|HasExternalReferences||SET [0:?] OF IfcExternalReferenceRelationship FOR RelatedResourceObjects||
Reference to an external reference, e.g. library, classification, or document information, that is associated to the property definition.
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Name of this enumeration.
|2||EnumerationValues||LIST [1:?] OF UNIQUE IfcValue||
List of values that form the enumeration.
Unit for the enumerator values, if not given, the default value for the measure type (given by the TYPE of nominal value) is used as defined by the global unit assignment at IfcProject.
All values within the list of EnumerationValues shall be of the same measure type.
|UR1||The attribute Name should be unique|
ENTITY IfcPropertyEnumeration SUBTYPE OF (IfcPropertyAbstraction); Name : IfcLabel; EnumerationValues : LIST [1:?] OF UNIQUE IfcValue; Unit : OPTIONAL IfcUnit; UNIQUE UR1 : Name; WHERE WR01 : SIZEOF(QUERY(temp <* SELF.EnumerationValues | NOT(TYPEOF(SELF.EnumerationValues) = TYPEOF(temp)) )) = 0; END_ENTITY;