Tip avoid data duplication in a class

A class can include child classes at any level of detail. When the class is used, all its child classes are online and loaded in memory.

It is therefore useless to duplicate a class information inside a child class. If any information of a parent class is necessary in a code executed for a child information, it is always possible to use APARENT.PROPERTY.

This type of duplication is inefficient because you have to add code to propagate the header value when it is modified.

There is an exception to this rule: when using a combined object pattern, the created detail class duplicates the data in the header interface class.