Relationship Types vs Relationships

Relationship Types vs Relationships

Relationship Type (Metamodel / M2)

A Relationship Type defines a kind of connection between elements.

• Created in the metamodel layer
• Has a name (e.g., "runs_on", "manages", "depends_on")
• Can have properties (e.g., a "manages" relationship might have a "since" date property)
• Needs Allowed Connections to specify which Node Types it can connect
• Found under Relationship Types in the Tree View

Relationship (Model / M1)

A Relationship is a concrete connection between two specific nodes.

• Created in the model layer
• Connects a source node to a target node
• Follows the rules set by Allowed Connections
• Has specific property values
• Shown as arrows/lines on the canvas
• Found under Relationships in the Tree View

How to Create Each

Creating a Relationship Type:

1. In the Tree View, find the Relationship Types section
2. Click the + button
3. Give it a name (e.g., "runs_on")
4. Add properties if needed in the Properties Panel
5. Important: Set up Allowed Connections to define which Node Types this relationship can connect

Creating a Relationship (Instance):

1. On the canvas, hover over a node to see connection handles (small circles)
2. Click and drag from a handle on the source node
3. Drop on the target node
4. If multiple relationship types are allowed, a popup lets you choose which one
5. The relationship appears as a line/arrow between the nodes

Example

Relationship Type (M2)	Relationships (M1)
runs_on	payment-service → web-server-01
manages	Alice → Bob
depends_on	auth-service → database-service