The optional deleteIfAbsent argument enables you to specify whether you want elements (for example, classes and properties) that exist in the JADE database but are not defined in the incoming schema file to be deleted.
You can also use the deleteMethodsIfAbsent and deletePropertiesIfAbsent arguments to provide you with more-detailed control over the deletion of missing methods and properties.
An application in the database that is used in a package is not deleted (over‑written) when a complete schema definition containing that application is loaded.
By default, undefined elements are deleted.