Page level validation to prevent duplicate data entry into the database

Question

Hello,
Can anyone please help me out with this issue.
I have a form with two items based on a table. I already have an item level validation to check for null. Now I would like to create a page level validation to check that duplicate data are not entered into the database. I would like to check the database when the user clicks on ‘Create’ button to ensure they are not inserting duplicate record. If data already exist, then show the error message and redirect them to another page. I am using apex 3.2
Thanks

Answer 1

Hi,
Have you tried writing a PLSQL function to check this?
I haven't tested this specifically, but something like this should work:
1) Create a Page Level Validation
2) Choose PLSQL for the method
3) Choose Function Returning Boolean for the Type
For the validation code, you could do something like this:
DECLARE
    v_cnt number;
BEGIN
    select count(*)
    into v_cnt
    from
    your_table
    where
    col1 = :P1_field1 AND
    col2 = :P2_field2;
    if v_cnt > 0 then return false;
    else return true;
    end if;
END;If the query returns false, then your error message will be displayed.
Not sure how you would go about redirecting after this page though. Maybe just allow the user to try again with another value (in case they made a mistake) or just press a 'cancel' button to finish trying to create a new record.
Amanda.