Re: Many-to-many question ...
Re: Many-to-many question ...
- Subject: Re: Many-to-many question ...
- From: Lachlan Deck <email@hidden>
- Date: Fri, 26 Oct 2007 09:49:28 +1000
On 25/10/2007, at 7:37 PM, Daniele Corti wrote:
> 2007/10/25, Lachlan Deck <email@hidden>:
>> You have two choices with M2M Join tables.
>> A<-->>AB<<-->B
>>
>> 1) flatten the relationships... so that you're adding to both sides
>> of relationship two records on either side of the join. Join
records
>> using EOGenericRecord and don't have any logic in them.
>>
>> A myA = (A)EOUtilties.createAndInsertInstance(ec, "A");
>> B myB = (B)EOUtilties.createAndInsertInstance(ec, "B");
>> myA.addObjectToBothSidesOfRelationshipWithKey(myB, "bs");
>
> How this work? Do you need to set the EOmodel in some way?
Flattening relationships involves creating a many-to-many join like
here:
http://wiki.objectstyle.org/confluence/display/WOL/Creating+a+Many+to
+Many+Join
Thank you, but is there a way in EOModeler? (really, I've never
completely understand how to user Entity Modeler)
Sure.
1) Select two entities (make sure you've given them a primary key
each, an entity name, external name)
2) Choose Property > Join in Many to Many
3) make sure join entity has its external name and entityName as
desired.
The concept in Entity Modeler is similar - but far less buggy....
i.e., select two entities, right-click, choose New Relationship...
and follow the prompts. I really suggest that you jump over to using
WOLips now. Really, the water is fine, there's lots of help available.
> 2) don't flatten the relationships
Otherwise, create normal toMany relationship from A to AB, and B to
AB in the modeler.
Usually I use this , but I like to continue learning new way to do
things ;-P
with regards,
--
Lachlan Deck
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