View DNDAF:SV-10a Systems Rules Model Subview

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Title

SV-10a Systems Rules Model Subview

Version & Date

1.6 See DNDAF Release History

Introduction

The SV-10a subview is part of the DNDAF System View.

The System View-10a (SV-10a): Systems Rules Model describes the rules that control, constrain or otherwise guide the actions within a system.

Purpose

The purpose of this sub-view is to allow understanding of behavioural rules and constraints imposed on systems and system functions.

Background

For the purpose of this sub-view, rules are “Statements that define or constrain some aspect of the enterprise.” This sub-view builds on the operational rules defined in the OV-6a to describe their physical implementation. Specifically, the SV-10a focuses on the constraints imposed on business processes or systems functionality by specific aspects of the system’s design or implementation.

Description

Definition

Systems rules are constraints on an architecture, on a system(s), or system hardware/software item(s), and/or on a system function(s). While other SV sub-views (e.g., SV-1, SV-2, SV-4, SV-11) describe the static structure of the System View (i.e., what the systems can do), they do not describe, for the most part, what the systems must do, or what it cannot do.

At the systems or system hardware/software items level, SV-10a describes the rules under which the architecture or its systems behave under specified conditions. At lower levels of decomposition, it may consist of rules that specify the pre- and post-conditions of system functions. Such rules can be expressed in a textual form, for example, “If (these conditions) exist, and (this event) occurs, then (perform these actions).”

Detailed Description

In contrast to the OV-6a, SV-10a focuses on constraints imposed by some aspect of operational performance requirements that translate into system performance requirements. At a lower level of detail, SV-10a focuses on some aspects of systems design or implementation. Thus, as the operational rules can be associated with the OV-5 series, the systems rules in SV-10a can be associated with SV-1 and SV-2 systems, system components, or with SV-4 system functions.

Systems rules can be grouped into the following categories:

  • Structural Assertion: These rules concern the implementation of business domain terms and facts that are usually captured in the file structures or physical database schemas. These assertions reflect static aspects of the implementation of business rules that may be already captured in the Logical Data Model (OV-7). (Sometimes these rules are embedded in application code.) Examples:
    • Terms: Entities, records.
    • Facts: Association between two or more terms (i.e., relationship).
  • Action Assertion: These rules concern some dynamic aspect of system functioning and specify constraints on the results of system functions or applications. Examples:

    • Condition: Guard or if portion of if- then statement; if the condition is true, it may signal enforcing or testing of additional action assertions
    • Integrity Constraint: Must always be true (e.g., a declarative statement).
    • Authorization: Restricts certain system functions or applications to certain human roles or class of users.
  • Derivation: These rules concern algorithms used to compute a derivable fact from other terms, facts, derivations, or action assertions.

Because the structural assertion rules are frequently captured in the OV-7, SV-10a usually focuses on the more dynamic action assertions and derivations rules.

Additional rule characteristics include:

  • Independent of the modeling paradigm used
  • Declarative (non-procedural)
  • Atomic (indivisible yet inclusive)
  • Expressed in a formal language such as:
    • Decision trees and tables
    • Structured English
    • Mathematical logic
    • Distinct, independent constructs

 

Subview DADM Elements

The DADM entities and attributes provided below are the elements that this sub-view is responsible for creating:

 

 

Presentation

  • Formal language e.g. structured text, decision tree

 

From section 3.24.7, volume 2:

Until a single methodology is selected to record the SV-10a, each architecture project may select the formal language in which to record its SV-10a. The notation selected should be referenced and well documented (i.e., there should be text books or articles that describe it and provide examples of its use).
...

Examples

See:

  • p132 Figure 3.24.1 in DND/CF Architecture Framework (DNDAF)  Volume 2: DND/CF Views and Sub-Views

Prerequisites

The SV-4 and OV-6a are prerequisites for this sub-view:

  • SV-4.Systems Rules Model uses the Systems Functionality Description.
  • OV-6a.System Rules are derived from the Operation Rules Model..

Note: SV-10a, 10b and 10c represent the dynamic aspect and behaviour of the system. They are closely related and whenever applicable these sub-views are modeled together.

 

See DNDAF Subview Dependencies

 

Comments

 

Other Frameworks

See also:

References


Category:Framework -> Specification
Category:Framework -> Subview

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