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entity-relationshiperd

Unknown symbol in ERD

I was searching for the meaning of the symbol marked in red in the image below, but I didn't get anything.

So, do you guys know what it means?

What are those?

Solution

  • It indicates a supertype/subtype relationship. The notation is used in Microsoft Visio, where it's called a category. A double horizontal line is used to indicate a complete category.

    In your image, Jurusan records information about the parent/supertype while Animasi, TKJ, RPL and Otomotif describe children/subtypes.

    Here's a video on the topic.

    Supertype/subtype hierarchies