Defining Derived Relationships

To define the rules for a Derived Relationship (DR), in the EA Main menu, choose Specialize / Model Expert / Manage Derived Relationships.

This shows:

1. The Derived relationships already defined in this repository.
2. Selecting one of these will show it’s definition: the relationship path, and some other information about the DR

To create a new DR:

1. Choose the starting element type and stereotype, and press ‘create new’.
   At the moment, Model Expert uses the underlying Element Type and stereotype, and not the meta-type as defined in an MDG. This means, for example in Archimate, if you want to include an Archimate Business Actor, you can’t just choose ‘Archimate_BusinessActor from the ‘element type’ list.
   Instead, you need to know that an Archimate Business Actor is implemented as a <<Archimate_BusinessActor>>Class.
2. This will open the derived relationship path, with the selected element type/stereotype at the top
3. Click through the connector types and element types to describe the path you want to take to a target element type. You may find it useful to have copy of your current meta-model available.
   If there are multiple routes between two element types, and you want to use both of them to create derived connectors, then you need to define two Derived Relationships.
4. When you reach the end of the sequence of connector- and element-types, click on the final elements type, then add all the other data which your DR needs:
   1. A name. This is just used to help you, and other modelers, identify the DR
   2. A connector type and (optionally) stereotype. When you use this DR to create a derived connector, this says what kind of EA connector Model Expert needs to create
   3. Title (optional). This becomes the name of the derived connector
   4. Notes. Just used used to describe this DR in more detail. Helps other models to choose the right DR.
   5. Connector Color. You may find it useful to give Derived Connectors a different color in your diagrams.
5. Then save the Derived Relationship definition. For the first DR you create, you will be asked for the place in your repository to save the DR details, which will be in new element of type <<derived relationship>>Artifact , with the DR definition stored in a tagged value called drDetails.

Example

In the example repository, find the Data for Derived Relationships package.

This shows a large, hard-to-understand Archimate diagram:

This diagram is big and hard because it shows a lots of types of element, and lots of connectors, but it’s the raw data that Derived Relationships will use. It shows how Archimate_BusinessActors are related to Archimate Components. Can you work which Business Actors relate to which Application Components ? This is the problem that DRs are designed to fix.

To create a DR which defines how Business Actors and Application Components are related:

1. Open Manage Derived Relationships from the top EA / Specialize / Model Expert menu
2. There should already be one defined, called ‘Business actor to Application Component’. Click that to see it’s definition.
3. To create another DR like that one, in the Create New part of the form, choose an element type (and optionally stereotype) where the DR will start, and press ‘Create New’
4. This shows the starting element type/stereotype, and all the connectors types which are linked to it
5. Then choose a connector type to see what element types are at the end of that connector,
6. Choose from those elements types, and continue, until you get to the element type toy want the DR to connect to.
7. Then choose the connector type/stereotype, direction, color and optionally a name to be attached to the connector. This name can be useful, because it lets you describe what the connection means in a way which is easy to understand.

When defining a new DR, you may find it useful to look at either :

• a diagram which contains the elements – and their intermediate connectors and elements
  OR
• a meta-model diagram which shows all of the elements and connectors in your model.

Apply the Derived Relationship to create some Derived Connectors

In the example model, find the diagram “Summary with DRs’. This is a selection of the start- and end-elemet from the supplied Derived Relationship “Business actor to Application Component’

Notes:

1. A DR is defined by a single path through your model. If you want to have additional paths, then create another DR, but make it create a DC with the same type, stereotype and color as the first one.
2. DRs can be defined by traversing connectors either forwards or backwards: this is shown on the ‘Derived Relationship path’.
3. In the list of starting element types and stereotypes, these are the low-level definitions from the EA repository, not the more friendly meta-type names, so you may need to check with your meta-mdoel diagram to get the right type & stereotype. For example, an ‘Archimate Business Actor’ is a <<Archimate_BusinessActor>>Class.
4. When choosing the connecor type and stereotype for your DCs, you can not choose connector types which are defined in any MDG. Only connector types from the standard set of EA connector types, the any stereotype you choose, can be selected

Editing DRs

You can edit the definition of a DR, but this not affect any DCs which have already been created. It will affect any new Cs which get created based on the DR.