I have created a form and table as a shared db in the network. Although i have set the users not allowed to edit the data in security right but i found that when they accidentally key something wrong in the existing form and close, then the data will automatically modified.

How should I prevent this happen, the user supposed can add entry but not edit the current data.

Thanks.

In the forms property sheet under the Data tab set Allow Edits to No. You may want to change a couple of the other events there as well.