Inheritance and associations

Hi, here a part of class diagram:

When i try to sync class diagram with ERD, i’ve the following error message:
[10:54:32] [Error] Offers: Class Class “Offers” is not allowed to have association due to the table per concret class inheritance strategy.

The inheritance strategy selected is “table per concrete class”.


Hi Guglielmo,

There is a limitation on mapping “Table per concrete class” associations to ERD.
Take “Table per subclass” as an example:

Saving either A, B or C will store a row in entity A, and the association will sync to D.AID foreign key reference A.
With “Table per concrete class”, all subclasses will store in their own table only, and independently. Saving B will not store a row in entity A, so the foreign key is invalid.

Please consider using other inheritance strategies.

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If you used the table per concrete class strategy, couldn’t you have multiple foreign keys in entity D each referencing tables A, B and C?

Your explanation is completely right.
But, reversing the cardinality between D and A should make the mapping legitimate and possible, since the foreign key will be sport by the many side. That is either the B or the C will have a foreign key to the D.
Unfortunately VisualParadigm refuse to sync the class diagram with ERD even in this case.