Hi Surajit,
I'm afraid it's a little more complicated than this. As Erik Ernst points out here, it is important to know the business logic behind the tables. This defines where your addition to the business logic has to be fitted.
You want to get a notifier when the item shifts or (possibly) changes its value.
The inventory of an item lives in the Item Ledger Entries table. Ledger entries are never inserted/modified/deleted directly in a form or page. So, putting code on the quantity field of the entry wouldn't have the desired effect. They will be created by a posting process, always utilizing T83 (Item Journal Line) and CU 22 (Item Jnl. - Post Line). So you could add your code in there, preferably in InsertItemLedgEntry(). When you also need a notification when the value changes (or something happens that needs a re-calculation of the value), then you also need to consider the Value Entries (T5802) and Item Application Entries (T339). Looking at this, you'll notice it's quite a lot of complicated code. For the Adjust Cost Item Entries batch job, NAV also needs a handle to know which items need to be adjusted. As I wrote in my previous post, this flag has at least a similar property like what you require. A quick search with Stati-Cal Prism shows the occurrences of this flag in NAV. So, that's where you need to put your code in.
with best regards
Jens
