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Qualified name of reference [message #1850339]

Fri, 25 February 2022 13:56

John Henbergs

Messages: 239
Registered: October 2020

Senior Member

Hi all,

I am writing some transformations in QVTo, and I have the following scenario.

In target metamodel I have a concept ConceptA referencing ConceptA1 (reference is named "a2a1"), where concept A1 has attribute name.
In source metamodel I have a concept ConceptB with attribute name.
I am writing a mapping rule:

mapping ConceptA :: conceptA2conceptB : ConceptB {
// and here I want to assign the name of concept A1 to B and I write the following:
result. name := self.a2a1.name;
}

It work this way, but I want wondering if there is another way on how to write this. Maybe something where I could only write:

result. name := self.name;

And this could be contained somewhere ...

Many thanks!

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Re: Qualified name of reference [message #1850344 is a reply to message #1850339]

Fri, 25 February 2022 15:53

Ed Willink

Messages: 7655
Registered: July 2009

Senior Member

Hi

The 'obvious' answer is to use a different mapping signature so that the new 'self' is the old 'self.a2a1'. For a single problem this might just make sense, but it is very unlikely to scale unless ConceptA and ConceptB are almost topologically identical.

An M2M is usually transforming models that are in some way different, and so you must expect to use computations/navigations to resolve the differences. Hiding the differences behind perverse mapping signatures will make your transformation less rather than more readable.

Regards

Ed Willink

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Re: Qualified name of reference [message #1850345 is a reply to message #1850344]

Fri, 25 February 2022 16:39

Christopher Gerking

Messages: 115
Registered: April 2011

Senior Member

Ed Willink wrote on Fri, 25 February 2022 10:53

The 'obvious' answer is to use a different mapping signature so that the new 'self' is the old 'self.a2a1'.

Exactly. Thus you should map both A and A2 to B. Such n:1 mappings can be realized using init sections:

mapping ConceptA :: conceptA2conceptB : ConceptB {
    init {
        result := self.a2a1.map conceptA12conceptB();
    }
}

mapping ConceptA1 :: conceptA12conceptB : ConceptB {
    result.name := self.name;
}

[Updated on: Fri, 25 February 2022 17:08]

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