====== P1-REQ-13-4-008 ======

[[dido:99_annexes:annex-d-requirements:part-01:start|Return to Part 1 Requirements]]

===== Statement =====

A [[dido:99_annexes:annex-b-terms-and-definitions:d:data_structure_instance|Data Structure Instance]] SHALL identify a populated occurrence of a [[dido:99_annexes:annex-b-terms-and-definitions:d:data_structure_definition|Data Structure Definition]].

===== Source =====

Part 1, Section 13.4: Core Conceptual Element Requirements.

===== Rationale =====

A Data Structure Instance represents a populated occurrence of a Data Structure Definition. This distinction separates the definition of a class of information from a specific occurrence of information that conforms to that definition.

This requirement supports traceability between definitions and instances and prevents a populated occurrence from redefining the information class.

===== Applies To =====

This requirement applies to Data Structure Instance references within the Conceptual Architecture.

It applies specifically to:

  * Populated information occurrences
  * Definition-to-instance relationships
  * Instance interpretation
  * Information traceability
  * Data Structure Instance descriptions

===== Verification =====

Verification SHALL confirm that each Data Structure Instance identifies a populated occurrence of a Data Structure Definition.

Verification activities include review checks confirming that:

  * Data Structure Instances identify populated occurrences
  * Each Data Structure Instance relates to a Data Structure Definition
  * Data Structure Instances do not redefine Data Structure Definitions
  * Instance references remain distinct from definition references

===== Traceability =====

Related source section:

  * [[fxdemo:01-part:13-conceptual-requirements:13-4-core-conceptual-element-requirements]]

Related requirement identifiers:

  * [[dido:99_annexes:annex-d-requirements:part-01:p1-req-13-4-001:start]]
  * [[dido:99_annexes:annex-d-requirements:part-01:p1-req-13-4-007:start]]
  * [[dido:99_annexes:annex-d-requirements:part-01:p1-req-13-4-012:start]]

===== Status =====

Draft

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