In a mandatory non-identifying relationship, the attributes that are migrated into the non-key area of the child entity are required in the child entity. Therefore, the foreign key cannot be null.
You can set the default null option in the Model Editor. If you assign a non-identifying relationship, either a mandatory or optional non-identifying relationship is automatically assigned based on your default null setting. However, you can change the null option in the Relationships editor to override the default setting.
A mandatory non-identifying relationship is drawn differently depending on the notation for your model:
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