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Adding attribute for relationship between entities [message #231046]

Fri, 22 May 2009 09:54

Alireza Missing name

Messages: 105
Registered: July 2009

Senior Member

Hello,

What I am trying to do is to have a gmf model with two entity e1 and e2
with a relationship and one attribute for the relationship. I do not want
to have an intermediate entity as relationship on my gmf diagram.

Best,

Alireza

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Re: Adding attribute for relationship between entities [message #231062 is a reply to message #231046]

Fri, 22 May 2009 10:05

Alexander Shatalin

Messages: 2928
Registered: July 2009

Senior Member

Hello Alireza,

Just use LinkMapping with only linkMetaFeature specified.

-----------------
Alex Shatalin

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Re: Adding attribute for relationship between entities [message #231071 is a reply to message #231062]

Fri, 22 May 2009 10:09

Alireza Missing name

Messages: 105
Registered: July 2009

Senior Member

Well, I did not get it really! This attribute is like a real attribute,
not just a runtime annotation or note.
I checked the link mapping and I did not find linkmetafeature, where is
it? and what is it?

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Re: Adding attribute for relationship between entities [message #231095 is a reply to message #231071]

Fri, 22 May 2009 11:16

Alexander Shatalin

Messages: 2928
Registered: July 2009

Senior Member

Hello Alireza,

> mapping and I did not find linkmetafeature, where is it? and what is
> it?
Sorry, it called "Target feature" in UI.

-----------------
Alex Shatalin

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Re: Adding attribute for relationship between entities [message #231101 is a reply to message #231095]

Fri, 22 May 2009 12:09

Alireza Missing name

Messages: 105
Registered: July 2009

Senior Member

It seems that this target feature determines the end direction of the
link, is it right?

Suppose that we have two entity: customer and items and the link between
them shows the customer buys the item. This relationship has a attribute
name quantity (how many of the item is bought by the customer), I want to
have it as a label for the link. This attribute first should be defined
somewhere in the ecore model, but where? and then how it can be added to
the gmf diagram, maybe as a label for link mapping or ...?

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Re: Adding attribute for relationship between entities [message #231132 is a reply to message #231101]

Fri, 22 May 2009 13:40

Alexander Shatalin

Messages: 2928
Registered: July 2009

Senior Member

Hello Alireza,

Ok. then you have to set following properties for the link mapping:
- Containment Feature = Customer.links
- Element = Link (EClass representing relationship and having "quantity"
attribute)
- TargetFeature = Link.items
Then in accordance with GMF tutorial you can add label for this link representing
quantity attribute.

As an example you can use Ecore diagram editor - diagram editor generated
by GMF. In this editor EReference links are representing this type of links.

-----------------
Alex Shatalin

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Re: Adding attribute for relationship between entities [message #231159 is a reply to message #231132]

Sun, 24 May 2009 16:59

Alireza Missing name

Messages: 105
Registered: July 2009

Senior Member

To tell the truth, I could not figure out what you sent me in last post :(
Could you please give more explanation or ...?

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Re: Adding attribute for relationship between entities [message #231178 is a reply to message #231159]

Mon, 25 May 2009 10:27

Alexander Shatalin

Messages: 2928
Registered: July 2009

Senior Member

Hello Alireza,

> To tell the truth, I could not figure out what you sent me in last
> post :( Could you please give more explanation or ...?
I suggest you to read all parts of GMF tutorial (http://wiki.eclipse.org/index.php/GMF_Tutorial)
- your use case should be covered there.

-----------------
Alex Shatalin

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Re: Adding attribute for relationship between entities [message #231215 is a reply to message #231178]

Mon, 25 May 2009 12:18

Alireza Missing name

Messages: 105
Registered: July 2009

Senior Member

Dear Alex Shatalin,

I have reviewed the gmf tutorials again, in tutorial three there is a part
that seems to be related to my problem, but it is not. It try to create 3
relationships based on relationship type attribute, wheres the attribute
of the relationship in my case can be arbitrary number.
Could you please help me to handle this? I have already spent a lot of
time for it ... :(

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