Entity tables or Map tables for "book" module

Greetings!

I'm beginning to create a custom module with the "book" functionality. It would be a list of articles grouped in "books" and then in "chapters". Each article is going to be text formatted with bbcode and "book" and "chapter" would only be there properties, so I could sort them the way book looks like (If I put all articles in one book and one chapter - it could be a simple dictionary). While all articles are not associated with particular image or album in galley (at least most of them) I decided to make a module because I want to have one seamless site and use one login/pass for all operations. Actually this (book) is the only functionality I need besides image galley.

So I managed to create tutorial module, made some views and need to move on, but stuck with table creation.

Articles looks pretty much as an entity, so Entity table might be a right choice, but I'm confused with few things:
When declaring an entity I need to define "parent-class-name". What should I do if my entity is not related to any existing entity? Should I define parent class as some default root class? How this choice influence the rest? What should I write in GalleryCoreApi::requireOnce('modules/core/classes/XXXXXXXX.class')

What would be the difference if I use Map tables? Are they just self sufficient tables with no relation to anything?

What is <schema-major> and <schema-minor>?

Thanks in advance.

I've just deleted them... how did you managed to post 5 times? It seems to be happening a lot recently, so if you can explain what happened I can maybe investigate and prevent it.

I can help.

serbanc - www.e-poze.ro