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Dependent / independent entities are a closely related concept. Dependent entities occur at the multiple end of the identifying relationship. They cannot exist without the independent entity at the other end. In addition, every inherited entity (if you are doing ER modeling) is considered to be dependent. A dependent entity's primary key includes the other entity's key as part. This is implied, not shown in the model. Dependent entities are automatically recognized and drawn with rounded corners.
Example of identifying relationship and dependent entity in the ER diagram.
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