Re: Many to many relationship... some problem
Re: Many to many relationship... some problem
- Subject: Re: Many to many relationship... some problem
- From: Amedeo Mantica <email@hidden>
- Date: Mon, 3 Aug 2009 18:29:27 +0200
why do you want to put the quantity in that table ???
leave the relationship alone
create a table " cart " with a relationship to product and a column
quantity.
then create a relationship cart to order
Regards
Amedeo
On 03/ago/09, at 18:16, Francesco Romano wrote:
On 03/ago/09, at 18:04, Lachlan Deck wrote:
On 04/08/2009, at 1:39 AM, Francesco Romano wrote:
On 03/ago/09, at 16:10, Lachlan Deck wrote:
On 03/08/2009, at 7:21 PM, Francesco Romano wrote:
Hi..
I'm having some problem with a many-to-many relationship.
I've two entities: Order and Product.
They have a many-to-many relationship, and an attribute: quantity.
The strange thing is that I don't see the OrderProduct model
generated...
Check the value of Class Name in the model. It's probably
EOGenericRecord. Change it to you.model.OrderProduct
You are right.. Now I see the class
Well.. to be honest I don't understand how many-to-many works...
(In WO.. I know the "DB-theory")...
OrderProduct orderProduct =
(OrderProduct)EOUtilities.createAndInsertInstance(ec,
OrderProduct.ENTITY_NAME);
// or
OrderProduct orderProduct = OrderProduct.createOrderProduct(ec,
product, order);
orderProduct.setQuantity(quantity);
ec.saveChanges();
Little problem.. the only method createOrderProduct has as
arguments: editingContext, quantity.
1) Your OrderProduct should (usually) have a compound primary key.
(orderID, productID). Both keys shouldn't allow null. Both
relationships (order, product) should be manditory. Then regenerate
your class.
I attach an image.. it's the OrderProduct entity.
<Picture 1.png>
So.. I can't set it's pks.
2) This is good. :-) You're dealing with objects now, not database
artifacts like pks and foreign keys. You'll be setting object
relationships not pk/fk relationships.
Simply fetch the product/order _objects_ and
orderProduct.setOrder(order);
orderProduct.setProduct(product);
With pks I meant that I don't have the setProduct and setOrder
method (and in the constructor).
with regards,
--
Lachlan Deck
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