Organising an Enterprise Architect Model

• If you have spent many hours creating a great EA Model, hopefully you want the rest of your organisation to use it as well. But how can you make it readable?
• Or maybe have you just picked-up a model which you created a few years back, only to be baffled by your own work. What exactly was this model all about, and where has all that great stuff gone ?
• Or perhaps you’ve inherited a model from someone else who isn’t available to tell you what’s in it. How are you supposed to sort out what’s complete and useful, from the ‘other stuff’?

Over the years, we’ve come across all of these several times, and have developed a few tricks to avoid them.

1. A Package is not a Bucket

The most important ‘thing’ in EA is definitely the Package. It’s also the simplest. Just a folder with stuff in it, right? Wrong.

The Package or rather the family of Packages which you create, say more about your model than anything else. If you just use them as a bucket to put things in, then you’re missing-out on a critical way to communicate the intent of your model.

2. Notes, notes, notes

I’ve been teaching UML and other modelling techniques for more than 15 years, so apologies to all former students for repeating this. If you’re in that select group, can you remember the most important UML (or BPMN, or SysML..) modelling construct ?

3. Single-purpose Packages

4. Different things get different stereotypes

The idea of the Stereotype is one of the key ideas of UML, which EA has extended to cover all the other model types it supports. So whether you’re creating SysML diagrams, BPMN business processes or Use Cases, you can use stereotypes.

So use them.

5. Status is everything, or Somewhere to Play

When you read a model, probably the most common problem is that you don’t know what the status of something is: a diagram, an element, or a whole package of the model.

Is this completed, signed-off and implemented, or just some ideas I had over coffee one day?

6. Public and Private diagrams

The great power of EA is that it allows us to create links between all kinds of elements, depending on what kind of problem we’re trying to solve.

There are several ways to create these links: the Relationship Matrix is a quick way, but diagrams are also very common. And this creates a problem for the reader.

Are they looking a ‘proper’ diagram, which they are supposed to understand, or is this a diagram which you just created to establish some relationships, and isn’t really for public use?

So get used to naming diagrams so that this is obvious, and to prevent accidental printing of these diagrams in documents.

Pick a naming convention for ‘do not print’ documents: we add ‘hidden’ in front of the document name. We’d like to use a diagram stereotype, but that doesn’t appear in the Project Browser. So ‘My untidy diagram’ becomes: ‘Hidden – my untidy diagram’. We also tick the box in the diagram properties to “Exclude image from RTF Documents”. Both the EA RTF generator and eaDocX will take this to mean ‘don’t print in any document’.

So now you’re free to create as many untidy diagrams as you like, and readers will know to ignore them.

7. Pick a meta-model, write it down, and stick to it

This final piece of advice is really a summary of all the others.

Each idea we’ve discussed above contributes to your meta-model.

If that sounds like a scary, super-technical idea, it isn’t.

All of your EA models already have a meta-model, whether you know it or not. The meta-model just says what kinds of ‘stuff’ is in your model.

• What kinds of elements have you used? e.g Requirements and Use Cases, but not internal requirements,
• How have you linked them together?
• What stereotypes have you used, and what does each one mean?
• How have you used things like Element Tests, the Glossary, or Project Tasks?

..so not really complicated. The meta-model is just your local modelling standards.

If you want to find out what your meta-model is, use Model Expert. It will draw a diagram of all the element types, stereotypes and links in your model. Be prepared for a surprise! Big models can be complicated!

This is a good reason to make your meta-model clear and simple. Pick a small number of elements, stereotypes and links, and use them consistently.

Communicating the meta-model is critical: one which only you understand is no use. It MUST be written down, preferably in the model itself, and taught to all of your team.

AND kept up-to-date, as your modelling style evolves, as it will certainly do.