When using the Edit and Create modes, certain user actions or updates in one field may require immediate updates in other UI elements.
For example, when a user selects a book in a bookshop app, its price is shown in the Price field. When they select another book, the Price field should display the new price immediately. This means you would need to get the corresponding value from the back end and update the appropriate field in the user interface.
In SAP Fiori elements, these actions are known as side effects. You can use the @Common.SideEffects annotation to indicate that changes in some UI elements (known as source entities or source properties) should trigger a request to update other UI elements (target entities or target properties).
There are some default side effects which apply to all apps. For example, if a user creates a new entity or a draft version in the list report or object page, the list binding of the parent page is refreshed to show the new item. These side effects apply automatically, and you don't need to annotate them. For more information, see Side Effects.
Note that the side effects request will not be triggered if there are any validation errors in the user interface. In this case, the errors should be resolved first.
For more examples of side effects you can add to your app, see Side Effect Annotations: Examples.