The following image below depicts an entity-relationship diagram (ERD) of a strong and weak entity.

The closest example, I found here (link), required that a foreign key be defined in the weak entity, interior_dimensions.

The weak entity ERD examples I came across, before creating the table interior_dimensions, did not depict any foreign key columns/attributes within them.

I would like to make sure if, adding the attribute model_id, to the table interior_dimensions, as a foreign key, is really necessary in this case, to depict the weak entity relationship, for MySQL.

enter image description here

  • 3
    Please provide the important SELECTs that will make use of this relationship. That will help judge the validity of the schema. – Rick James Feb 4 '19 at 3:20

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