How to define owned element types

Owned elements (subordinates) are elements that live inside a parent element and render in a compartment on diagrams — like attributes inside an entity.

1. Create the owned element type

1. In your M2 metamodel’s element type layer, create a new element type (e.g., “Attribute”)
2. In its Properties, open Subordination and tick Is Subordinate. Elements of this type are then created inside an element of another type, not from the Palette, and the heading reads Subordination · subordinate
3. Add properties to it (e.g., “Data Type” as an enumeration, “Is Required” as Boolean)
4. Configure basic notation (fill colour, icon)

2. Configure the parent to accept owned elements

1. Select the parent element type (e.g., “Entity”)
2. In the Properties panel, open Subordination. Under Subordinate Types, click + Add Subordinate Type. The button is available once at least one type in the metamodel is marked Is Subordinate
3. Fill in the entry:
   • ID — a unique identifier (e.g., “attributes”)
   • Label — display name (e.g., “Attributes”)
   • Classifier — the owned element type (e.g., “Attribute”)
   • Display template — how each owned element renders (e.g., {name} : {Data Type})

3. Add a compartment

Still on the parent element type’s notation, add a compartment:

1. Add a new compartment entry
2. Set content type to subordinates
3. Set subordinate type ID to the ID you defined above
4. Set label and show label as desired

4. Create owned elements at M1

1. Select an M1 instance of the parent type
2. Right-click > New Owned Element (or similar)
3. Choose the subordinate type
4. Name the element and fill in its properties

The owned element appears inside the parent’s compartment on diagrams.

Display template syntax

Template	Example output
{name}	email
{name} : {Data Type}	email : String
{name}{Is Required? [*]:}	email* (if required) or email (if not)