The API has a set of error classes that inherit the built-in Progress.Lang.AppError class. These classes encapsulate the most common error conditions. All errors are thrown back to your application, which can catch or throw them. You do not typically need to know what type of error is displayed or reference the error in your application code. If your application does not catch the error or use the ROUTINE-LEVEL, ON ERROR UNDO, THROW statement, the error messages display like any OpenEdge error message.
The API also provides some error handling mechanisms that you can also add to your application that work specifically with data errors returned by the DataAdminService.