Designing SQL database to represent OO class hierarchy

Question

I\'m in the process of converting a class hierarchy to be stored in an SQL database.

Original pseudo code:

abstract class Note
{
   int id;
         


        

Answer 1

I'd grativate towards option A myself.

It also depends a bit on your usage scenarios, for example will you need to do lots of searches across all types of notes? If yes, then you might be better off with option A.

You can always store them as option A (one big table) and create Views for the different sub-notes if you so please. That way, you can still have a logical seperation while having good searchability.

Generally speaking, but this might be close to a religious discussion so beware, I believe that a relational database should be a relational database and not try to mimic an OO structure. Let your classes do the OO stuff, let the db be relational. There are specific OO databases available if you want to extend this to your datastore. It does mean that you have to cross the 'Object-relational impedance mismatch' as they call it, but again there are ORM mappers for that specific purpose.