ADF how to add an existent object to collection

Question

I have three tables,
PRODUCT, PRODUCT_GROUP, PRODUCT_GROUP_LINK.
relationship between tables is
PRODUCT_GROUP (one-to-many) PRODUCT_GROUP_LINK (many-to-one) PRODUCT
Problem is,
I can not add a new record to the PRODUCT_GROUP_LINK table with ADF :(
If I use "Create" button for Iterator "ProductGroupLinkCollection",
after "Commit" command ADF automatically try add new PRODUCT_GROUP,
but I need to use existent PRODUCT_GROUP from PRODUCT_GROUP table.
What do you think about this problem?
Thanks.

Answer 1

Hi Arum,
What I would most suggest is reading the ADF Developer's Guide (For Forms/4GL developers, if that describes your background). Before you start creating your web UI, you need to create business components. From your description of this problem, you'll need at least the following:
- An entity object based on PRODUCT_GROUP_LINK (by default, it will be called ProductGroupLink).
- A view object based on that entity object (by default called ProductGroupLinkView).
- A view object based on a query along the lines of "SELECT ID, NAME FROM PRODUCT_GROUP" (say, ProductGroupView)
- A view object based on a query along the lines of "SELECT ID, NAME FROM PRODUCT" (say, ProductView).
- An application module with instances of all three view objects
When you have all that, you'll want to let the user select a row from ProductGroupView and one from ProductView, and use the ID attributes for those rows to create a new row for ProductGroupLinkView. (You could make the ProductGroupLinkView instance a detail of either ProductGroupView or ProductView, which would automatically populate one of the attributes. There's a way to make a VO instance a detail of two others, but IIRC it's a lot more trouble than just populating the other attribute manually.) That will have the effect of adding an existing product to an existing product group.
But check out the ADF developer's guide first. There's also a very good book, by Peter Koletzke and Duncan Mills, called "Oracle JDeveloper 10g for Forms Developers", that is very useful if you're not very familiar with business components.
Best,
Avrom