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[Teneo] Dynamic EMF, References [message #1051461]

Sun, 28 April 2013 21:00

Thomas Vetsch

Messages: 2
Registered: April 2013

Junior Member

Hi community,

I've done some work with the dynamic EMF approach which is explained here.

The listed example is very simple and easy to work with, but I stuck at some points and would like to ask the communitity for some help.

The following code is used to create dynamic references.

// A course always uses one SchoolBook
EReference courseBook = efactory.createEReference();
courseBook.setName("courseBook");
courseBook.setEType(schoolBookEClass);
courseBook.setContainment(false);
courseEClass.getEStructuralFeatures().add(courseBook);

With default settings, Teneo generates the mapping of the references as Many-To-One.

When i set the property "JOIN_TABLE_FOR_NON_CONTAINMENT_ASSOCIATION" to false and set the reference upperBound to "UNBOUND_MULTIPLICITY" the result is a One-to-Many reference in the mapping file.

My problem is, that i need to choose between 1:1, 1:n and n:m during the creation of these dynamic references and by now I wasn't able to get that right.

Is this even possible and what can I do to generate the desired mappings?

Please Help

Thanks in advance.

Thomas

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Re: [Teneo] Dynamic EMF, References [message #1051791 is a reply to message #1051461]

Mon, 29 April 2013 08:19

Martin Taal

Messages: 5468
Registered: July 2009

Senior Member

Hi Thomas,
Setting the upperbound is the way to change something from n:1 to 1:n. The 1:1 and n:m are bi-directional associations.

Somewhat of a summary for you:
- many-to-one (example a sales order has one currency, one currency is used in many sales orders): an ereference in the
order eclass to the currency eclass, the ereference has upperbound of 1
- one-to-many (example a sales order has sales order lines): an ereference in the order eclass to the orderline eclass,
the ereference has upperbound of unbounded, as the order lines are contained in the sales order, the containment of the
ereference is true
- one-to-one (example a person has a personinfo eclass): bidirectional, 2 ereferences from person to personinfo and vice
versa, in both ereferences set the upperbound to 1, set the eopposite of both ereferences (one ereference has the other
ereference as the opposite)
- many-to-many: same setup as one-to-one, only set the upperbound for both ereferences to unbounded

gr. Martin

On 04/29/2013 04:53 AM, Thomas Vetsch wrote:
> Hi community,
>
> I've done some work with the dynamic EMF approach which is explained
> http://wiki.eclipse.org/Teneo/Hibernate/Dynamic_EMF_Tutorial.
>
> The listed example is very simple and easy to work with, but I stuck at some points and would like to ask the
> communitity for some help.
>
> The following code is used to create dynamic references.
>
> // A course always uses one SchoolBook
> EReference courseBook = efactory.createEReference();
> courseBook.setName("courseBook");
> courseBook.setEType(schoolBookEClass);
> courseBook.setContainment(false);
> courseEClass.getEStructuralFeatures().add(courseBook);
>
>
> With default settings, Teneo generates the mapping of the references as Many-To-One.
> When i set the property "JOIN_TABLE_FOR_NON_CONTAINMENT_ASSOCIATION" to false and set the reference upperBound to
> "UNBOUND_MULTIPLICITY" the result is a One-to-Many reference in the mapping file.
> My problem is, that i need to choose between 1:1, 1:n and n:m during the creation of these dynamic references and by now
> I wasn't able to get that right.
>
> Is this even possible and what can I do to generate the desired mappings?
>
> Please Help
>
> Thanks in advance.
>
> Thomas
>
>

--

With Regards, Martin Taal

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