How do you extend enterprise architecture meta models to keep large-scale collaborative modelling manageable?
When enterprise architecture modelling moves beyond a single expert working alone — across teams, organisations, time zones, and languages — the meta model that was perfectly adequate for small-scale work begins to break down. Ownership conflicts, information overload, incompatible versions, and variable data quality all emerge as serious practical obstacles. This 2008 presentation by Graham McLeod, delivered at EMMSAD 2008 (Exploring Modelling Methods for Systems Analysis and Design), addresses these challenges head-on with a set of formal but pragmatic extensions to EA meta models and meta meta models, developed through real-world experience building and operating the EVA collaborative repository. The core constructs introduced include context — a powerful, reusable mechanism that operates at the meta meta level and addresses domain, ownership, authority, timeframe, status, and language in a unified way; relationship typing, which brings precision to how model elements connect; and a model type abstraction that subsumes graphical models, documents, reports, and user interfaces under a single coherent concept. A three-layer object architecture — implemented in Smalltalk — is shown to be essential for the flexibility required, with filters implemented as a specialisation of model type and time, version, and baseline tracking unified through relationships. The resulting conceptual model is notably compact given the range of challenges it addresses, and the presentation is candid about both the expressiveness achieved and the performance challenges encountered in implementation. For practitioners building or evaluating EA repository tooling, this is a rare account of what the meta model level actually needs to look like in production.
Originally presented by Graham McLeod at EMMSAD 2008 (Exploring Modelling Methods for Systems Analysis and Design), Montpellier, France, June 2008.