21 - Configuring your Many-to-Many Link Type

📖 Task Introduction

In relational databases, a many-to-many join across tables requires an intermediate join table. A similar concept exists in the Ontology, and in this exercise, you'll configure a many-to-many join between your passenger and flight alert object types.

🔨 Task Instructions

1. From the object type Overview page, scroll down to the Link Types block and click ⊕ Create new link type.
2. In the Choose an object type dropdown, select the [yourName] Flight Alert object type you created in Exercise 2.
3. Select Many as the cardinality for your Flight Alert object type and then agree to Change cardinality when prompted.
4. OMA will then ask you to define the join table that will enable the many-to-many relationship between your passengers and your flight alerts.
5. Select the passenger_flight_alerts dataset in your Ontology Project: Flight Alerts folder.
6. In the column dropdown for each object type, choose the respective primary keys: passenger_id for the Passenger object type and alert_display_name for Flight Alert.
7. Click Save in the top right corner.