2007/10/25, Lachlan Deck <email@hidden>:
On 25/10/2007, at 11:17 AM, Shagor Ghani wrote:
> Have a quick question around join tables storing M2M
> relationships. I need
> to store a M2M relationship and created a table for it using
> Property>Join
> in Many-to-Many option from within EOModeler itself. This table
> has two
> columns, id1 and id2, both of which are primary and which together
> produce a
> unique record. In my code, I've been doing creating new rows into
> this
> table using the standard
> object.addObjectToBothSidesOfRelationshipWithKey(
> object, key ) call. Now, though, I also need to store additional
> values
> within this record, for example a boolean bit indicating whether
> the record
> is active or not. How is this done? If I manually add a 3rd
> attribute
> column, what call is then used to update/create new record(s)?
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?
2) don't flatten the relationships
A myA = (A)EOUtilties.createAndInsertInstance(ec, "A");
AB myAB = (AB)EOUtilties.createAndInsertInstance(ec, "AB");
B myB = (B)EOUtilties.createAndInsertInstance(ec, "B");
myAB.setSomeOtherKey
(...);
myA.addObjectToBothSidesOfRelationshipWithKey(myAB, "abs");
myAB.addObjectToBothSidesOfRelationshipWithKey(myB, "abs");
with regards,
--
Lachlan Deck
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