While a script is making changes to a model, Modeler locks the items that are being changed.
You can minimize disruption to other model users by ensuring that the script that makes changes to a model appears only within the special transaction functions. Any script within the following functions will make changes to the model through a transaction:
Making changes to the model through the preceding functions also ensures that you can undo any changes made. In addition, you can see the changes made by the script without having to refresh your Modeler views.
On Delete and Derivation Script scripts do not have any functions specifically for making changes to the model.