Toad World® Forums

Exclusive ors

Is there a plan to provide arcs (exclusive ors) in the modelling tool?

I will check it with the team and let you know.

Regards,
Lukas

No, we haven’t talked about it. I will raise this question and will let you know.

Anyway, you can reach similar functionality under logical model using inheritance between three entities. When it’s converted to PER, you get only the two childs with triggers being created and ensuring the exclusivity.

Regards,
Lukas

Yes, I had noticed the exclusive inheritance and thought you might refer to it. That’s a work around, but if the exclusive relationship is to two parent entities, it doesn’t work. I have used the ellipse to spell it out, but if the entities moved, it’s a manual process to maintain the ellipse.

I use my enterprise data model to work with business users, and we have a lot of sub-types that are modelled for independent attributes and relationships. None of these are exclusive. I think the exclusive relationship is easier to understand, but it is nice to know that in a physcial transformation, using exclusive inheritance generates triggers. Is that just for Oracle databases, or is a feature for other rdbms?

Hi Dawn,

During LER to PER conversion, triggers are generated for all the databases that support triggers with the exception of MySQL, because MySQL triggers can’t provide the needed functionality.

Regards,
Lukas