Convert module sigle user environment to multiuser

Question

Hello
Currently module supports single user. Now, we have to make it to support multiple users.
There are certain problems with current form module if it is used as multi user environment.
For example, multiple users are running this module at a time and retrieving same value simultaneously in ITEM# field by pressing the ACQUIRENEW# button these items are already exist 1036, 1037, 1038, 1039......eg. if one user run this module and get item# 1036, second user also run this form and get the same item# 1036, third user also run this form and get the same item# 1036 but second should get 1037 and third user should get 1038 at the same time.
Second user cannot get item# 1037 until first user commit the value the item# 1036 but our client working in multiuser environment where at the same time so many user run this form and first user got 1036 second got 1037 third got 1038 an so on...
You have to make sure that duplicate product# should not be entered.
any one can give a sample code please help me this is urgent.
thanks in advance.
regards,
deemy

Answer 1

If you are putting this into a multiuser environment then:
"Second user cannot get item# 1037 until first user commit the value the item# 1036 "
Means you must introduce serialisation so that effectively only a single user can access the process to a acquirenew#
If this is what you want to achieve then you may have to go back to the old table method of generating sequence values.
If you have a table solely to manage the new value then when the user asks for a new value you can select from the table for update with nowait this will stop any other user getting a value until your user commits or rolls back their transaction.
At that point there is a free for all when a new/or the same user can lock the table again.
This will meet your requirement, but I think you should look at your design, perhaps use a sequence and consider how essential it is to maintain an unbroken sequence of item# (I think there are numerous threads on this site which have talked about maintaining this type of sequence) as this will STOP everyone except one person working with a new value and is not often the intention of a multiuser environment.