
Thanks for your further response, Nicola.
Linking Enrollment to LabSessionNr is correct, as Enrollment already contains the relevant Course. Of course, many lab sessions may have the same number, but this is not a problem.
In modeling, one may often choose between using a derivation rule or subset constraint.
As ...

Hi Nicola
Please see the attached pdf file for further thoughts on your example and its relational mapping in NORMA. I think this shows a more realistic way to model the example that avoids the mapping issue that you raised.
Cheers
Terry

Hi Nicola
I get a different relational mapping result when I use NORMA. Please see the attached pdf file for some discussion on this issue.
Cheers
Terry

To meet your objective in ORM, you could derive a relationship that is the union of the two other relationships, then subset from the given relationship to the derived one. For example, consider the binary relationships with predicates R, S and T from A to B. Now create a derived predicate U from A to B. so that forall x, y [xUy if (xRy v ...

I assume you mean slide 25 of Lab 4. The square brackets are around role names. NORMA automatically adds the square brackets when you enter the role name. To add a role name, rightclick the role box and enter the name in the Name property.
Cheers
Terry

Hi Gordon
Yes, an irreflexive ring constraint is equivalent to a valuecomparison constraint with the inequality operator. E.g. a simple irreflexive constraint on a binary predicate R formalizes as forall x not xRx, and a corresponding valueinequality constraint formalizes as forall x, y (xRy > ~x=y). It's easy to prove ...

Hi Jeff
Which file do you mean by "Tutorial 1"?
If you mean NORMA Lab 1 (which I updated on 2016 August 31), then slides 2224 don't have any verbalization on them. Please clarify.
Cheers
Terry

ORM recognizes three kinds of object types: entity type (e.g. Country); domain value type (e.g. CountryCode) often shortened to "value type", and data type (e.g. string). Value types carry more semantics than data types (e.g. the CountryCodes 'CH'and 'DE' are based on Latin and German ...

Dear Berhanu
Congratulations on earning your master's degree!
And thank you for your kind words of appreciation for my support. It was a pleasure discussing ORM with you.
Kind regards
Terry

Hi Marc
While we do support those other display options at the conceptual level, their use at the relational level seems inappropriate. Perhaps you could describe the specific relational notation(s) you would like us to support.
Cheers
Terry