The SEDRIS Data Representation Model
APPENDIX A - Classes
Property Set Index Control Link

Class Name: Property Set Index Control Link

Superclass - <Control Link>

Subclasses

This DRM class is concrete and has no subclasses.

Definition

An instance of this DRM class specifies an <Expression> instance that determines the index field value of all target <Property Set Index> instances, thus controlling which <Property Set> instance is referenced by each such <Property Set Index> instance.

NOTE  Since each controlled <Property Set Index> instance may be bound to a different <Property Set Table Group> instance, and thus to a different primary <Property Set Table> instance, the fact that their index values are the same does not mean that the set of <Property Set Index> instances controlled by a given <Property Set Index Control Link> instance reference the same <Property Set> instance.

Primary Page in DRM Diagram:

Secondary Pages in DRM Diagram:

Example

  1. A tree canopy appears different at different times of the year, with a different colour and texture. This can be achieved by using a different <Property Set> instance for each period of the year. Each <Property Set> instance contains the appropriate <Colour> instance(s) and <Image Mapping Function> instance(s). A <Property Set Index Control Link> instance is used to allow the appropriate <Property Set> instance to be selected.

FAQs

What does a <Property Set Index Control Link> instance control?

A <Property Set Index Control Link> instance C controls the value of the index stored in each <Property Set Index> instance that references C.

Can a <Property Set Index Control Link> instance be used to change which <Property Set Table> component of a <Property Set Table Group> instance is referenced?

No. The index always refers to the primary <Property Set Table> component.

Can a <Property Set Index Control Link> instance be used to switch from one <Property Set Table Group> instance to a different <Property Set Table Group> instance?

No. The link to the <Property Set Table Group> instance is an association within the transmittal, and associations cannot be changed dynamically.

Constraints

Composed of (two-way) (inherited)

Component of (two-way)

Inherited Field Elements

SE_String description; 1

Field Elements

SE_Integer_Positive expression_index; 2

Notes

Fields Notes

description

The description field specifies a text description of the purpose of the <Control Link> instance.

expression_index

The expression_index field specifies the <Expression> component, the value of which controls the index of the affected <Property Set Index> instances.


Prev: Property Set Index. Next: Property Set Table. Up:Index.

Last updated: July 26, 2006 Copyright © 2006 SEDRIS