What are constants in Appian?

Constants in Appian are values that can be called from any expression throughout an application. They play a crucial role in ensuring that certain values remain unchanged, which can help prevent errors and improve maintainability. Constants can be used for various purposes, such as storing default settings, configuration values, or any data that should not vary during the execution of the application.

For instance, if a particular numeric value is referenced in multiple places across your application—like a tax rate or a fixed discount amount—it is sensible to store this value as a constant. This ensures that if it ever needs to be updated, you only need to change it in one location, which reduces the risk of inconsistencies.

The other options, while related to data structures and programming concepts, do not accurately define what constants are in the context of Appian. Constants are specifically designed to hold fixed values for use in expressions, which underscores their importance in building reliable and efficient applications.