Hi, i have made a set of perl modules and CGIs for creating online exercises (multiple choice, etc). It's called OEME and its hosted on CodigoLivre (http://www.codigolivre.org.br/projects/oeme), if you fell like taking a look at it. Well, the thing is, I created a superclass Question, and subclasses to it to actually be each kind of question. Question has the normal acessor functions, that are used in all Question::* classes.

Each question is set on a PostgreSQL database, each type on a differente table. Each id can be gotten with the following SQL command SELECT NEXTVAL('tablename_id'). That works for all subclasses. So I defined a constant in each subclass, called table, that contains the name of the table, and a _get_new_id function in the Question superclass, that does the select according to the table name of $self, wich will, off course, call the table function(constant) of the subclass.

Now, everything I ever read about OO (even in the moral liberal perl world) says one should never let superclass acess subclass data. So I ask, is this technique I describe actually superclass acessing subclass data? And if so, is it justifiable to do it? And is there another, more correct in the OO sense, way to do it?

Thanks in advance,
Paulo Schreiner

Edit by tye

In reply to Superclass acessing sublass data by pauloschreiner

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