You might need to make changes to your schema as your organization's informational needs change. For instance, if you never required a fax number before on your User object, but now you need to, you can create a new User class that has Fax Number as a mandatory attribute, and then begin using the new User class to create User objects.
You can modify an existing class by adding one or more optional attributes. You can modify an existing schema by either extending the schema or by deleting classes or attributes.
You can add mandatory attributes to a class only while creating a new class.
You can add optional attributes to existing classes anytime your organization's needs change or when you are preparing to merge trees.
You can extend the schema of a tree by creating a new class or attribute. You don't need to extend the schema, but you can do so with Schema Manager. You can extend the schema as needed to meet organizational needs. For example, you may want to extend your schema if your organization requires special footwear for employees and you need to keep track of employee shoe sizes. You might want to create a new attribute called Shoe Size and then add it to the User class.
You can delete a class anytime a class has become obsolete, but prior to deleting it, you should first make sure the class is not being used by any NDS object. You cannot delete a class until all instantiated objects using the class have been deleted
You can delete an attribute anytime an attribute has become obsolete, but you should make sure the class is not being used by any NDS object. You cannot delete an attribute that is in use by any class.