Toad World® Forums

Atributes to M:N Relation (LER)


#1

Hello,

I am trying to make logical model with TDM, and I don find the way to add attributes and relationships to a relation M:N in a logical model.

I know a relationship M:N is made a object when converting to PER, then I can work on it to complete whith attributes and relations. But no way to have a logical representation of this.

I have been searching help and forums but nothing related to this issue. Any Help?

Thanks in advance.


#2

Hi,

model three tables instead of two and create identifying relationships, add attributes to the third entity…

BTW: if you don’t use inheritance, maybe physical model can be better for you. When you draw M:N relationship in physical model, the third entity is created automatically.

More about model type selection:
http://blogs.inside.quest.com/modeling/2010/01/13/model-type-selection-and-why-fks-don’t-migrate-to-child-entities-in-logical-model/

Regards,

Vaclav


#3

Ok, I though that the LER functionality was focused on the ER model specificaction. Where yo can define a verb in a relation between entities represented by a diamond, and add attributes to this diamond.

But at this moment it seems that not all the ER specification is covered by this Tool. Hope in future version it will be added.

Thanks for the fast response.

Regards, NaN


#4

Hi,

Toad Data Modeler doesn’t support all notations, that’s why you currently cannot work with diamonds, but you should be able to draw diagram that can be converted to physical model and finally generate SQL code for target database.

Here you can see various notations:

Regards,

Vaclav