Re: Many to many relationship... some problem
Re: Many to many relationship... some problem
- Subject: Re: Many to many relationship... some problem
- From: Francesco Romano <email@hidden>
- Date: Mon, 3 Aug 2009 18:51:46 +0200
On 03/ago/09, at 18:49, Amedeo Mantica wrote:
On 03/ago/09, at 18:40, Francesco Romano wrote:
On 03/ago/09, at 18:29, Amedeo Mantica wrote:
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
Because I was thinking to save the cart in the cookies.. Should I
save the cart of every customer even if they don't place an order?
(this is a question.. I don't know how things work..)
yes, so you can give customers choice to save cart and finish order
later, if the order is not finished within some days you trash the
cart
Amedeo
Yeah.. I have to change the model a bit :p
Btw.. how can I trash the cart automatically? Is it possible with WO?
Francesco
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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