Mandatory Non-Identifying Relationships in the Logical Model
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:
- IDEF1X notation draws a dashed line with a solid dot on the child end.
- IE notation draws a dashed line with a cross on the parent end. The child end indicates the cardinality with:
- Crows feet with a cross and a circle (Zero, One or more)
- Crows feet with a cross (One or more)
- A cross and a circle (Zero or one)
- A dashed line (Exactly n)
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