Want help in validation

Question

i'm bulding a project with ADF Fusion web application (ADF BC) with Jdeveloper 11g
i want to make some kind of validation
the problem is that
I have a table contains Employee Id , Employee Salary Deduction
I want that
The total Salary Deductions For any employee Per Month can't exceed the emplyee Salary
For Example
Alex Salary is 2000$
and this is the deductions
Employee || Salary Deduction
Alex ||100$
Alex ||50$
Alex ||200$
Alex || 100$
The total deductions her is 450$
i don't want the total deductions to exceed the employee Salary
but i don't know how to achieve this with ADF

Answer 1

Grant,
product selling price must be greater than product min price, but what happens if someone else is changing the product min price in a different transactionActually, there is no issue whatsoever there - the problem comes from multi-row validation. In your example, a simple check constraint solves the problem. Let's assume that user 1 updates the selling price while at the same time, user 2 updates the minimum price. When user 1 commits, he doesn't see user 2's changes, so his change saves successfully. When user 2 commits, his change will violate the check constraint and thus not save. Furthermore, with the default ADF behaviour, user 2 will not even be able to commit, because he will receive the "another user has updated this row" error first. If you instead implement the rule in ADF BC, the "another user has updated this row" error will prevent the issue as well.
However, in the OP's scenario, there are multiple rows involved, so unless you have some type of concurrency control built-in (either via explicit locks manually coded or by using the materialized view trick), you are exposed to multi-user problems.
John