P7 – Physical Data Model

The P7 Physical Data Model View defines the structure of data used by the Resource Types in the architecture.

Concerns Addressed

  • System Design.
  • Data Schema Design.
  • Message / Protocol Specification.
  • Data Architecture.
  • Database Design.

Background

The P7 View is one of the architectural products closest to actual system design in the NAF. It is used to describe how the information represented in the L7 Logical Data Model View is implemented.

While the mapping between the logical and physical data models is relatively straightforward, the relationship between the components of each model (e.g. entity types in the logical model versus relational tables in the physical model) is frequently one-to-many or many-to-many.

Usage

  • Specifying the data elements exchanged between systems (thus reducing the risk of interoperability errors).
  • Definition of physical data structure (input to system design).

Representation

  • Formal text data modelling language (e.g. SQL, ISO10303-11, etc.).
  • Topological (connected shapes).
  • UML class diagram.

Detailed View Description

The P7 View is an implementation-oriented data model that is used to describe how the information requirements represented in the L7, Logical Data Model, are actually implemented for a given solution. The entities specified in the P7 View represent data elements (from the P3, Resource Connectivity View).

There should be a mapping from a given logical data model (L7) to the physical data model (P7) if both models are used. This mapping is often not trivial (e.g. there may be conditional mappings), in which case a formal mapping language such as ISO10303-14 should be used against the data model or individual entities.

Figure 3-691: SAR Physical Data Model

Standards associated with entities are also often identified in the development of the P7 view; these should be recorded in the A8, Standards View.

Figure 3-702: Example P7 UML Class Diagram

Note that a P7 view can also simply be a text schema (e.g. in the case of SQL or ISO10303-11).

Key Elements and Their Relationships

Meta-Model

The detailed meta-model and element list for P7, Physical Data Model, is at paragraph 4.5.9.