How to change value in database using oracle form

Question

- i have a table called mobilephone with quantity column
- i already created a list of quantity inside my form with elements 1-5
- what i want is when i press a button inside my form it will automatically deduct the value i chose from list to the database
- for example if my quantity inside the table is 10, when i chose 2 in the list it will become 8 in the table

Answer 1

Hi,
I agree with Roel, but it might not be enough for you. This depends on the usage, and more specifically the number of concurrent users that might do the same kind of transactions.
If user1 has selected 5 phones, and at the same time user2 has selected 6 phones, then only at the moment they hit the "Apply Changes" or "Create" button, will they know whether they the number of phones they require are actually available.
If this scenario is highly unlikely to occur, I would go with the trigger as Roel indicated. If it is likely to occur, you might want to consider using Javascript to immediately check the availability through a database function call. This will require some database changes, that I could elaborate on. But I will wait until you indicate that this is indeed what you need.
Good Luck!
Remco