IfcExternalReference
Definition from IAI: An IfcExternalReference is the
identification of information that is not explicitly represented in the current
model or in the project database (as an implementation of the current model).
Such information may be contained in classifications, documents or libraries.
Only the Location (e.g. as an URL) is given to describe the place
where the information can be found. Also an optional ItemReference as a
key to allow more specific references (as to sections or tables) is provided.
The ItemReference defines a system interpretable method to identify the
relevant part of information at the data source (given by Location). In
addition a human interpretable Name can be assigned to identify the
information subject (e.g. classification code).
IfcExternalReference is an abstract supertype of all external
reference classes.
HISTORY: New Class in IFC
Release 2x to generalize means of referencing available in IFC Release 2.0.
Use Definitions
See the use definitions given at the subtypes of
IfcExternalReference.
EXPRESS specification:
|
|
|
|
|
|
| WR1
|
:
|
EXISTS(ItemReference) OR EXISTS(Location) OR EXISTS(Name);
|
|
|
|
Attribute definitions:
| Location
|
:
|
Location, where the external source (classification, document or library). This can be either human readable
or computer interpretable. For electronic location normally given as an URL location string, however
other ways of accessing external references may be established in an application scenario.
|
| ItemReference
|
:
|
Identifier for the referenced item in the external source (classification, document or library). The
internal reference can provide a computer interpretable pointer into electronic source.
|
| Name
|
:
|
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).
|
Formal Propositions:
| WR1
|
:
|
One of the attributes of IfcExternalReference should have a value assigned.
|
Inheritance graph
|
|
| ENTITY IfcExternalReference;
|
|