Creating master detail rows

Question

using adf/bc with jsf. I have defined a master detail relationship between two entities. This relationship is a composition relationship. The entities are related by a view link which link the master and detail view objects. i have a need to create/insert a master row and a detail row programmatically "on the fly" so that when the jsp renders, the user will see blank inputs for both the master and detail view objects. The problem is that the primary key of the master record is not known at creation time ( it will be entered by the user) and therefore the detail record cannot be created by the framework because of the unknown value of the parent's primary key. I was hoping the following section in the adf guide would eliminate my problem, but it doesn't appear to:
This is from section 26.7.3.2 of the adf developer's guide
Note: An alternative to the programmatic technique discussed
above, which solves the problem at the J2EE application layer, is the
use of deferrable constraints at the database layer. If you have control
over your database schema, consider defining (or altering) your
foreign key constraints to be DEFERRABLE INITIALLY DEFERRED.
This causes the database to defer checking the constraint until
transaction commit time. This allows the application to perform DML
operations in any order provided that by COMMIT time all appropriate
related rows have been saved and would alleviate the parent/child
ordering described above. However, you would still need to write the
code described in the following sections to cascade-update the foreign
key values if the parent’s primary key is assigned from a sequence.
This approach did not help in allowing me to create the detail record without first knowing the value of the parent's primary key record in a composition relationship. The only thing i've found to work is define the relationship as just an association, and not a composition. However, this is a true one to many (composition) relationship and i would like to take advantage of some of the features of the framework that are there when a relationship is defined as a composition relationship. Is there any way to do what i need to do with a composition relationship defined between these two entities? Thanks.

Answer 1

Hi,
I guess you need a "Cascading LOVs".
1) Create viewObject for country values list. Named VO1.
2) Create viewObject for state values list. Named VO2.
3) Create view criteria for (bind variable) VO2 which can restrict the result by country.
4) Create view accessor to get VO1.
5) Create view accessor to get VO2. Define the bind variable value which can provide country info dynamically. I guess it should be a Groovy expression.
6) Create country LOV on step 4) view accessor.
7) Create state LOV on step 5) view accessor.
Done
On the view layer, you may enable PPR between country and state attributes.
Todd