Describe the capabilities of and use cases for validation rules.
Validation rules verify user input when records are created or updated. Validation conditions are defined in formula expressions and return TRUE or FALSE. If a condition returns TRUE, a warning message is shown to users and records are not saved.
If all user input is valid, the formula expressions return FALSE and records are saved. If any user input is invalid, the formula expressions return TRUE and a custom error message is displayed, preventing the record from saving.