In OutSystems web applications you can create the following Actions:
- Screen Actions
- Server Actions
When you have for example a web screen that lists Contacts, you will need to execute some logic before the screen is displayed to fetch the list of Contacts from the database.
In OutSystems, you execute that logic in a Preparation action:
You don't have to explicitly invoke the Preparation action because it is automatically executed before a screen is rendered. It is right place to add all the logic you want to execute before the screen is displayed, such as setting values to variables and fetching data from the database.
You can also add a Preparation action to your Web Blocks.
In a web screen to update a Contact, for example, you will need to define an action that reacts to the user interaction of clicking the "Save" button and execute the logic to update the Contact. In OutSystems web applications you do this in a Screen Action:
Screen Actions allow you to run logic when the user interacts with the screen, such as clicking on a button or a link.
You can also add Screen Actions to your Web Blocks.
An application typically has its own business rules. In OutSystems you can create Server Actions to encapsulate the logic that implements the business rules of your application and use them in other actions, such as Preparation actions, Screen Actions or other Server Actions:
You can set a Server Action as a function and use it directly in expressions.