An identifying relationship is a relationship between two entities in which an instance of a child entity is identified through its association with a parent entity, which means the child entity is dependent on the parent entity for its identity and cannot exist without it. In an identifying relationship, one instance of the parent entity is related to multiple instances of the child.
In IDEF1X notation, an identifying relationship line is drawn as a solid line with a diamond or a filled circle at either end of the line.
In IE notation, an identifying relationship line is drawn as a solid line with crows feet.
You can create an identifying relationship when you add a relationship using the Relationships editor, on the diagram window, or using the Model Explorer.
Note: Primary key attributes are automatically migrated from a parent entity to a child entity, so you do not need to enter any foreign keys in the child.
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