Class Name: Geometry ID Control Link

Superclass - Control Link

Definition

The specialized Control Link used to provide the connection between an ordered aggregation of Expressions and the target fields of a Geometry ID.

The expr_index field is a 1-based index into the ordered aggregation of Expressions, and is used to select the specific Expression that controls the value of Geometry ID's ID field.

Primary Page in DRM Diagram:

• 17

Secondary Pages in DRM Diagram:

• 13

Example

1. Consider a Geometry Model containing a Geometry Node, which has a Geometry ID component. In this case, the data provider wishes to ensure that each Geometry Model Instance uses a unique Geometry ID for this node.

   In order to do this, the data provider attaches a Geometry ID Control Link to the Geometry ID object, where the ID field's controlling Expression is a Variable. In this way, each Geometry Model Instance can supply a different Literal Expression to be plugged into the Geometry ID Control Link's Variable, so that each Geometry Model Instance provides a different ID for the Geometry Node within the Model.

FAQs

Constraints

Composed of (two-way)(inherited)

• one or more {ordered} Expressions

Component of (two-way)

• one or more Geometry IDs

Inherited Field Elements

Field Elements

Notes

Fields Notes

description

 A text description of what the Control_Link is for

expr_index

 index of the expression whose value controls
 the ID of the affected <Geometry ID> object.