Adjust posting order of new/modified entities in ADF BC

Question

Hi,
I have any ADF application which has two tables:
BUDGET
BUDGET_ID: NUMBER(12) -- Which is a sequence from DB sequence BUDGET_SEQ
BUDGET_DETAIL
BUDGET_ID: NUMBER(12) -- Foreign key to BUDGET(BUDGET_ID)
LINE: NUMBER(7) -- A sequential number based on the master with one based, for ex: BUDGET_ID/LINE may be 1234/1, 1234/2, 1234/3 ..., and 1235/1, 1235/2, 1235/3...
CONSTRAINT BUDGET_DETAIL_UK UNIQUE (BUDGET_ID, LINE)
In JDev 11.1.1.2.0, the Model project has 2 entity objects, 2 view objects, 1 association and 1 viewlink, they are BudgetEO, BudgetVO, BudgetDetailEO, BudgetVO, Budget_BudgetDetail_Assoc and Budget_BudgetDetail_ViewLink (based on the association) to access the BUDGET and BUDGET_DETAIL table.
When we mark budget, we will create a row in BudgetVO and then create some rows in BudgetDetailVO. In the BudgetDetailVO, we always reorganize the "Line" attribute to be sequential after create new row and delete row. The code like the following:
private void reorganizeLineNo() {
RowSetIterator iter = this.createRowSetIterator(null);
try {
int idx = 1;
while (iter.hasNext()) {
Row row = iter.next();
row.setAttribute("Line", new Number(idx++));
} finally {
iter.closeRowSetIterator();
My problem is if we add/remove BudgetDetail(s) in the following sequence, it will violate DB constraint BUDGET_DETAIL_UK:
1. Create bRow1 in BudgetVO
2. Create bdRow1 in BudgetDetailVO under bRow1, here bdRow1.Line=1
3. Commit. Everything works fine
4. Set bRow1 as current row
5. Add a new bdRow2 in BudgetDetailVO under bRow1, here bdRow2.Line=2
6. Remove bdRow1, here will call reorganizeLineNo(), so bdRow2.Line=1 now.
7. Commit, exception occurs for violating DB constraint BUDGET_DETAIL_UK.
The SQL running in DB is in order of (presodo):
1. INSERT INTO BUDGET (BUDGET_ID) VALUES (BUDGET_SEQ.nextval);
2. INSERT INTO BUDGET_DETAIL (BUDGET_ID, LINE) VALUES (:TheBudgetId, 1);
3. Commit
4. INSERT INTO BUDGET_DETAIL(BUDGET_ID,LINE) VALUES (:TheBudgetId, 1); -- Violate BUDGET_DETAIL_UK
5. DELETE FROM BUDGET_DETAIL WHERE BUDGET_ID=:TheBudgetId AND LINE=1
6. Commit.
How to adjust to posting order in ADF BC to post the DELETE in step 5 before the INSERT step 4?
Many thanks!
Regards,
Thomas.

Answer 1

This work flows screens for this kind of constrain violation. On solution would be to commit the operation after inserting line 2, and then deleting line 1.
I think this is a poor design, because you will run in trouble if more the one user is working in your system.You have to edit a bunch of rows only you deleted one. It's never a good idea to have an editable pk or even a part of it.
I would try to decouple the line number from the primary key all together. You could easily generate the line number when you show the lines (i.e. using an index of the iterator). This way you can use a sequence number as pk for the line item. The order of the line items is simply the order of the sequence numbers (which will never displayed to the user).
Timo