On a general perspective, the series will deal with three main issues:
- Scope: how to bring under a common conceptual and pragmatic roof business, organizational, and systems engineering considerations
- Representations: how to ensure a formal, integrated, and ecumenical description of all the aspects concerned
- Interoperability: how an open-source EA ontology can enable a seamless integration with engineering platforms
With regard to the specificity of enterprise architecture, the light will be put on:
- Drawing the line between enterprise and system architectural concerns
- Using representative topics to expound modeling alternatives
- Linking modeling alternatives to standard design patterns
These issues will be considered with regard to the activities and development of a restaurant, with episodes loosely set across EA workshops:
- Enterprise workshop: organization, business domains and processes, supporting- systems interfaces, locations, and communication channels
- Domains workshop: symbolic representation of business objects and rules
- Applications workshop: development of systems functions business applications
- Systems workshop: operations and deployments
The case study will be carried out as an open workshop using the OWL 2 / Protégé implementation of the Caminao kernel. The kernel itself (Cake_WIPg) and the case study (A Diner in bOwls) can be consulted on the Protégé portal.
This opening episode is focused on inventories and meant to serve as a pilot for the whole series.
As far as information systems are concerned, EA requirements should first decide what is to be represented, and why; and then determine which subset is already represented by supporting systems.
Inventories provide a smooth learning curve to modeling issues, starting with the representation of physical items and the necessary distinction between what can be known from the environment, and what must be managed by the enterprise.
Models: Products & References
Models are symbolic representations of environments and managed objects and activities with regard to given objectives. The challenge is to draw a line between relevant categories and irrelevant ones.
In theory there are two basic modeling approaches: (a) the modeling of conceptual hierarchies with inventories defined as features or, (b) the modeling of inventories with references to externally defined conceptual hierarchies. In practice the first (conceptual) approach would tie the enterprise information architecture to an external reference system, or compel the enterprise to define and maintain its own conceptual model in line with the ones set in the environment.
To begin with, management will want to know the contents of the diner’s pantry without being too specific about the details of inventories. To that end an enterprise architecture pattern (≈) is introduced to deal with management issues independently of the nature and use of the elements considered. Typically, such a pattern for products references should include name, code, what pertains to shelf life, and the quantities at hand.
Types & Instances
Taking into account the kinds of food, actual inventory items can be managed, and therefore represented, at different levels, depending on accounting rules:
- Fungible items, like oil or butter
- Batches of unidentified items, like eggs, cheeses, or poultry.
- Items identified individually as to ensure traceability, for example pieces of beef (regulatory context) or pricey bottles of wine (accountability).
Include connectors are used when homogeneous identification mechanism is not necessary or cannot be established.
Inventory items can be managed wholesale and locally (e.g., cheeses or average wines) at the enterprise level, or specifically (e.g., specific wines, cheeses, or poultry), with references to external information (e.g., nutrients).
Compared to unidentified items, the representation of identified ones raises issues that should be dealt with at the enterprise level.
Taking quarter beef for exemple, regulations may require traceability, and consequently the identification of inventory items through:
- Collective items, each representing homogeneous sets of quarter beefs
- Inventory items representing identified quarter beefs
Models & Meta-models
Meta-models are models of models: instead of representing relevant individuals in environment, they represent relevant categories in models.
With regard to inventories, the critical distinction is set by identification mechanisms:
- System or process: identities are used to manage representations; for instance batches of poultry with regard to expiry dates.
- Enterprise or organization: identities are used to manage business objects; for instance pricey bottles of wine.
- Environment: identities are used to align business objects with their external counterpart; for instance quarter beefs.
These distinctions are best represented through templates & meta-models, e.g.:
The alignment of models and meta-models is achieved using:
- mapTerrit_ connectors, between enterprise and external objects representations, e.g., inventory items for Quarter Beef (symbolic objects) would be mapped to physical objects identified externally
- realization_ connectors, within enterprise objects representations
It must be noted that these options can be combined, e.g., bottles of wines Grand Cru could be also identified externally by vineries.